diff --git a/README-CN.md b/README-CN.md
index 612b7ad..9cecc66 100644
--- a/README-CN.md
+++ b/README-CN.md
@@ -260,6 +260,17 @@ $options->setReconnectPolicy(true,3);
 $options->setReconnectPolicy(true,3,100);
 ```
 
+> Ack 超时时间
+
+* `ack()` 会阻塞等待 broker 返回的 `ACK_RESPONSE`，通过 request ID 进行匹配
+* 如果在超时时间内没有收到匹配的响应，`ack()` 会抛出 `RuntimeException`
+* 如果在等待响应期间发生重连，重连后重新发送的 ack 同样受此超时时间限制
+* 默认值为 30 秒
+
+```php
+$options->setAckTimeout(30);
+```
+
 > 不循环接收消息，且平滑退出
 
 ```php
@@ -464,6 +475,7 @@ $reader->close();
     * setDeadLetterPolicy()
     * setSubscriptionInitialPosition()
     * setReconnectPolicy()
+    * setAckTimeout()
     * setSchema()
 * ReaderOptions
     * setTopic()
diff --git a/README.md b/README.md
index 8c0e2bf..33ebb21 100644
--- a/README.md
+++ b/README.md
@@ -272,6 +272,17 @@ $options->setReconnectPolicy(true,3);
 $options->setReconnectPolicy(true,3,100);
 ```
 
+> Ack timeout
+
+* `ack()` blocks waiting for the broker's `ACK_RESPONSE`, matched to the request by request ID
+* If no matching response arrives within this timeout, `ack()` throws a `RuntimeException`
+* Also applied to each resend after a reconnect occurs while waiting for the response
+* Default is 30 seconds
+
+```php
+$options->setAckTimeout(30);
+```
+
 > Not loop Receive And Smooth exit
 
 ```php
@@ -478,6 +489,7 @@ $reader->close();
     * setDeadLetterPolicy()
     * setSubscriptionInitialPosition()
     * setReconnectPolicy()
+    * setAckTimeout()
     * setSchema()
 * ReaderOptions
     * setTopic()
diff --git a/src/Consumer.php b/src/Consumer.php
index 435d185..9b14831 100644
--- a/src/Consumer.php
+++ b/src/Consumer.php
@@ -13,7 +13,11 @@
 use Pulsar\Exception\MessageNotFound;
 use Pulsar\Exception\OptionsException;
 use Pulsar\Exception\RuntimeException;
+use Pulsar\Proto\BaseCommand\Type;
+use Pulsar\Proto\CommandAckResponse;
 use Pulsar\Proto\CommandMessage;
+use Pulsar\Util\Buffer;
+use Pulsar\Util\Helper;
 use Pulsar\Util\Packer;
 use SplPriorityQueue;
 use SplQueue;
@@ -182,13 +186,12 @@ public function receive(bool $loop = true): Message
             }
         }
 
-
         // nack
         $this->executeInternalNack();
 
         // ping
         $this->ping();
-
+    
         if (is_null($response)) {
             if (!$loop) {
                 throw new MessageNotFound();
@@ -209,28 +212,11 @@ public function receive(bool $loop = true): Message
             return $this->receive($loop);
         }
 
-
-        $consumer = $this->getPartitionConsumer($commandMessage->getConsumerId());
-
-        /**
-         * @var $messages array<Message>
-         */
-        $messages = Packer::decode($commandMessage, $response->getBuffer(), $consumer->getTopic());
-
-        foreach ($messages as $message) {
-
-            // Save Options to Message Object
-            $message->setOptions($this->options);
-
-            $this->messageQueue->enqueue($message);
-        }
-
-        $consumer->decrement(sizeof($messages));
+        $this->enqueueCommandMessage($commandMessage, $response->getBuffer());
 
         return $this->messageQueue->dequeue();
     }
 
-
     /**
      * @return array<Message>
      * @throws IOException
@@ -248,18 +234,87 @@ public function batchReceive(bool $loop = true): array
     }
 
     /**
+     * Sends the CommandAck and blocks for its CommandAckResponse, correlated by request ID.
+     *
+     * While waiting, any MESSAGE frame that arrives first (the broker may deliver one before
+     * the ACK_RESPONSE, since the connection is asynchronous) is queued rather than discarded.
+     *
+     * Unlike receive(), this does not reconnect on a dropped connection: a lost connection
+     * mid-ack throws IOException immediately, regardless of ConsumerOptions::getReconnectPolicy().
+     *
+     * This is deliberate, not an oversight. A dropped connection during ack() means the
+     * broker may already have decided this consumer is gone and redelivered the message to
+     * another consumer on the same subscription (Shared/Key_Shared). Throwing immediately
+     * gives the caller an honest, timely signal instead of a client library quietly retrying
+     * underneath it.
+     *
      * @param Message $message
-     * @return void
-     * @throws \Exception
+     * @return CommandAckResponse|null
+     * @throws IOException
+     * @throws RuntimeException
      */
-    public function ack(Message $message)
+    public function ack(Message $message): ?CommandAckResponse
     {
         if (!$message->canAck()) {
-            return;
+            return null;
         }
 
-        // send CommandAck
-        $this->getPartitionConsumer($message->getConsumerID())->ack($message);
+        $requestId = Helper::getRequestID();
+        $this->getPartitionConsumer($message->getConsumerID())->ack($message, $requestId);
+
+        $deadline = microtime(true) + $this->options->getAckTimeout();
+
+        do {
+            $remaining = $deadline - microtime(true);
+            if ($remaining <= 0) {
+                throw new RuntimeException('Timed out waiting for ACK response.');
+            }
+
+            $response = $this->eventloop->wait((int) ceil($remaining));
+
+            if (null === $response) {
+                continue;
+            }
+
+            $baseCommand = $response->getBaseCommand();
+
+            $commandType = $baseCommand->getType();
+
+            if (Type::CLOSE_CONSUMER_VALUE === $commandType->value()) {
+                // only abort if it's the consumer this message belongs to; the connection
+                // may be shared with other partition consumers that closed independently
+                if ($baseCommand->getCloseConsumer()->getConsumerId() === $message->getConsumerID()) {
+                    throw new RuntimeException(
+                        'The consumer was closed before the message acknowledgment was confirmed.'
+                    );
+                }
+                continue;
+            }
+
+            if (Type::MESSAGE_VALUE === $commandType->value()) {
+                $this->enqueueCommandMessage($baseCommand->getMessage(), $response->getBuffer());
+                continue;
+            }
+
+            if (Type::ACK_RESPONSE_VALUE === $commandType->value()) {
+                $ackResponse = $baseCommand->getAckResponse();
+
+                if ($ackResponse->getRequestId() !== $requestId) {
+                    throw new RuntimeException('ACK response request ID does not match.');
+                }
+
+                if ($ackResponse->hasError()) {
+                    $msg = $ackResponse->hasMessage() ? $ackResponse->getMessage() : $ackResponse->getError()->name();
+                    throw new RuntimeException(
+                        sprintf('The broker rejected the acknowledgment: %s', $msg),
+                        $ackResponse->getError()->value()
+                    );
+                }
+
+                return $ackResponse;
+            }
+
+        } while (true);
     }
 
 
@@ -358,4 +413,35 @@ protected function getPartitionConsumer(int $consumerID): PartitionConsumer
         return $this->consumers[ $consumerID ];
     }
 
+    /**
+     * Decodes a MESSAGE frame's payload into Message objects, queues them locally, and
+     * decrements the partition's available flow-control permits accordingly.
+     *
+     * Shared by receive() and ack()'s wait loop, since a MESSAGE frame can arrive while
+     * ack() is waiting on the same connection for an unrelated ACK_RESPONSE -- it must be
+     * queued here rather than discarded, or the message would be silently lost.
+     *
+     * @param CommandMessage $commandMessage
+     * @param Buffer $buffer
+     * @return void
+     */
+    private function enqueueCommandMessage(CommandMessage $commandMessage, Buffer $buffer)
+    {
+        $consumer = $this->getPartitionConsumer($commandMessage->getConsumerId());
+
+        /**
+         * @var array<Message> $messages
+         */
+        $messages = Packer::decode($commandMessage, $buffer, $consumer->getTopic());
+
+        foreach ($messages as $message) {
+            // Save Options to Message Object
+            $message->setOptions($this->options);
+
+            $this->messageQueue->enqueue($message);
+        }
+
+        $consumer->decrement(sizeof($messages));
+    }
+
 }
diff --git a/src/ConsumerOptions.php b/src/ConsumerOptions.php
index dee11f0..652ceca 100644
--- a/src/ConsumerOptions.php
+++ b/src/ConsumerOptions.php
@@ -70,6 +70,13 @@ final class ConsumerOptions extends Options
      */
     const ENABLE_RECONNECT = 'reconnect';
 
+    /**
+     * Max seconds to wait for an ACK_RESPONSE before giving up, default 30 seconds
+     *
+     * @var int
+     */
+    const ACK_TIMEOUT = 'ack_timeout';
+
     /**
      * @param array $topics
      * @return void
@@ -259,6 +266,26 @@ public function getNackRedeliveryDelay()
     }
 
 
+    /**
+     * @param int $seconds
+     * @return void
+     */
+    public function setAckTimeout(int $seconds)
+    {
+        $this->data[ self::ACK_TIMEOUT ] = $seconds;
+    }
+
+
+    /**
+     * @return int|mixed
+     */
+    public function getAckTimeout()
+    {
+        $timeout = $this->data[ self::ACK_TIMEOUT ] ?? 30;
+        return $timeout <= 0 ? 30 : $timeout;
+    }
+
+
     /**
      * @return mixed|string
      * @throws \Exception
diff --git a/src/PartitionConsumer.php b/src/PartitionConsumer.php
index 96cae6e..bd43596 100644
--- a/src/PartitionConsumer.php
+++ b/src/PartitionConsumer.php
@@ -12,10 +12,12 @@
 
 
 use Pulsar\Exception\IOException;
+use Pulsar\Exception\RuntimeException;
 use Pulsar\IO\AbstractIO;
 use Pulsar\Proto\BaseCommand\Type;
 use Pulsar\Proto\CommandAck;
 use Pulsar\Proto\CommandAck\AckType;
+use Pulsar\Proto\CommandAckResponse;
 use Pulsar\Proto\CommandCloseConsumer;
 use Pulsar\Proto\CommandFlow;
 use Pulsar\Proto\CommandRedeliverUnacknowledgedMessages;
@@ -155,10 +157,11 @@ public function flow()
 
     /**
      * @param Message $message
-     * @return void
+     * @param int $requestId
+     * @return CommandAckResponse
      * @throws IOException
      */
-    public function ack(Message $message)
+    public function ack(Message $message, int $requestId)
     {
         // send CommandAck
         $command = new CommandAck();
@@ -167,6 +170,7 @@ public function ack(Message $message)
         $command->addMessageId($message->getMessageIdData());
         $command->setTxnidLeastBits(null);
         $command->setTxnidMostBits(null);
+        $command->setRequestId($requestId);
         $this->connection->writeCommand(Type::ACK(), $command);
     }