diff --git a/mq-demo/ReadMe.md b/mq-demo/ReadMe.md
index fed4912..df27b46 100644
--- a/mq-demo/ReadMe.md
+++ b/mq-demo/ReadMe.md
@@ -446,4 +446,133 @@ void buildExchangeTimeoutTest2() {
         rabbitTemplate.convertAndSend(EXCHANGE, ROUTING_KEY, "消息层面超时自动删除【" + i + "】", postProcessor);
     }
 }
-```
\ No newline at end of file
+```
+
+## 死信队列
+
+> [!NOTE]
+> **死信（Dead Letter）**：满足以下任一条件的消息：
+> 1. 被消费者拒绝且不重新入队（`requeue=false`）
+> 2. 消息在队列中超过TTL时间
+> 3. 队列达到最大长度限制（溢出）
+
+**概念：**当消息因上述原因无法被正常消费时，会被标记为死信（Dead Letter），并可通过死信交换机（DLX）路由到死信队列。
+
+**产生原因：**
+
+1. **拒绝：**消费者拒绝消息`basicNack`/`basicReject`，并且不把消息重新放入源目标队列，`requeue=false`。
+2. **溢出：**队列中消息数量达到限制。比如队列最大只能存储10条消息，且现在已经存储了10条消息，此时如果再发送一条消息进来，根据先进先出原则，队列中最早的消息会变成死信。
+3. **超时：**消息达到超时时间未被消息。
+
+**死信处理方式：**
+
+- **丢弃**
+  适用于对业务无影响的非关键消息（需明确丢弃的监控手段）。
+- **入库**
+  将死信持久化到数据库，便于后续分析或人工干预。
+- **监听（推荐）**
+  - 配置独立的死信交换机和队列，与业务逻辑解耦。
+  - 消费者专注处理异常消息（如补偿、告警等）。
+
+### 测试环境
+
+#### 搭建死信环境
+
+**创建死信交换机**
+
+exchange.dead.letter.video
+
+![image-20250519151418248](./images/image-20250519151418248.png)
+
+**创建死信队列**
+
+queue.dead.letter.video
+
+![image-20250519151430393](./images/image-20250519151430393.png)
+
+**绑定死信队列**
+
+routing.key.dead.letter.video
+
+![image-20250519151451777](./images/image-20250519151451777.png)
+
+#### 搭建正常环境
+
+> [!WARNING]
+> 必须为正常队列配置以下参数才能生效：
+> - `x-dead-letter-exchange`：指定死信交换机
+> - `x-dead-letter-routing-key`：指定死信路由键
+
+**正常交换机**
+
+exchange.normal.video
+
+**正常队列**
+
+queue.normal.video
+
+这时设置最大长度为10，一次接受10条消息，超出后进入死信。
+
+![image-20250519152200270](./images/image-20250519152200270.png)
+
+**正常路由键**
+
+routing.key.normal.video
+
+到正常的队列中指定正常的交换机和正常路由键。
+
+![image-20250519152552486](./images/image-20250519152552486.png)
+
+### 测试Code
+
+#### 因拒绝产生
+
+**含义：**
+
+- 本来时监听正常队列的，处理一些逻辑，但是因为某些原因消息成死信了，消息转到死信队列中。
+- 这时候，在下面又监听了死信队列，死信队列可以监听到成死信的消息。
+
+```java
+/* 测试死信---监听正常队列 */
+@RabbitListener(queues = {"queue.normal.video"})
+public void processMessageNormal(String dataString, Channel channel, Message message) throws IOException, InterruptedException {
+    log.info("监听正常队列----接受到：{}", dataString);
+    channel.basicReject(message.getMessageProperties().getDeliveryTag(), false);
+}
+
+/* 测试死信---监听死信队列 */
+@RabbitListener(queues = {"queue.dead.letter.video"})
+public void processMessageDeadLetter(String dataString, Channel channel, Message message) throws IOException, InterruptedException {
+    log.info("监听死信队列----接收到：{}", dataString);
+    channel.basicAck(message.getMessageProperties().getDeliveryTag(), false);
+}
+```
+
+向正常队列发送消息
+
+![image-20250519153747525](./images/image-20250519153747525.png)
+
+#### 因超时或溢出
+
+在上设置了最大长度为10，如果发送40条那么有30条是溢出的，这时会进入死信队列中。
+
+测试时注释掉监听死信队列和正常队列的代码，之后看UI界面折线图。
+
+```java
+/* 因超时或移除产生死信 */
+@Test
+void buildExchangeOverflowTest() {
+    String EXCHANGE = "exchange.normal.video";
+    String ROUTING_KEY = "routing.key.normal.video";
+
+    for (int i = 0; i < 40; i++) {
+        rabbitTemplate.convertAndSend(EXCHANGE, ROUTING_KEY, "因超时或移除产生死信【" + i + "】");
+    }
+}
+```
+
+从图中可以看出，是分多批进行的。
+
+在之前设置中，消息最大接受是10，最多只能接收到10条消息，之后溢出消息进入死信，其中有10条消息是因为延迟，进入了死信。
+
+![image-20250519154653646](./images/image-20250519154653646.png)
\ No newline at end of file
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diff --git a/mq-demo/src/main/java/cn/bunny/mq/mqdemo/mq/listener/MessageListenerOrder.java b/mq-demo/src/main/java/cn/bunny/mq/mqdemo/mq/listener/MessageListenerOrder.java
index 01d0c20..9bef018 100644
--- a/mq-demo/src/main/java/cn/bunny/mq/mqdemo/mq/listener/MessageListenerOrder.java
+++ b/mq-demo/src/main/java/cn/bunny/mq/mqdemo/mq/listener/MessageListenerOrder.java
@@ -68,4 +68,17 @@ public class MessageListenerOrder {
         channel.basicAck(message.getMessageProperties().getDeliveryTag(), false);
     }
 
+    /*      *//* 测试死信---监听正常队列 *//*
+    @RabbitListener(queues = {"queue.normal.video"})
+    public void processMessageNormal(String dataString, Channel channel, Message message) throws IOException, InterruptedException {
+        log.info("监听正常队列----接受到：{}", dataString);
+        channel.basicReject(message.getMessageProperties().getDeliveryTag(), false);
+    }
+
+     *//* 测试死信---监听死信队列 *//*
+    @RabbitListener(queues = {"queue.dead.letter.video"})
+    public void processMessageDeadLetter(String dataString, Channel channel, Message message) throws IOException, InterruptedException {
+        log.info("监听死信队列----接收到：{}", dataString);
+        channel.basicAck(message.getMessageProperties().getDeliveryTag(), false);
+    } */
 }
diff --git a/mq-demo/src/test/java/cn/bunny/mq/mqdemo/MqDemoApplicationTests.java b/mq-demo/src/test/java/cn/bunny/mq/mqdemo/MqDemoApplicationTests.java
index 397c6ef..93a0770 100644
--- a/mq-demo/src/test/java/cn/bunny/mq/mqdemo/MqDemoApplicationTests.java
+++ b/mq-demo/src/test/java/cn/bunny/mq/mqdemo/MqDemoApplicationTests.java
@@ -85,4 +85,15 @@ class MqDemoApplicationTests {
             rabbitTemplate.convertAndSend(EXCHANGE, ROUTING_KEY, "消息层面超时自动删除【" + i + "】", postProcessor);
         }
     }
+
+    /* 因超时或移除产生死信 */
+    @Test
+    void buildExchangeOverflowTest() {
+        String EXCHANGE = "exchange.normal.video";
+        String ROUTING_KEY = "routing.key.normal.video";
+
+        for (int i = 0; i < 40; i++) {
+            rabbitTemplate.convertAndSend(EXCHANGE, ROUTING_KEY, "因超时或移除产生死信【" + i + "】");
+        }
+    }
 }