diff --git a/src/main/java/com/yunhai/userbase/common/GlobalExceptionHandler.java b/src/main/java/com/yunhai/userbase/common/GlobalExceptionHandler.java
index 2e740f9..6c26903 100644
--- a/src/main/java/com/yunhai/userbase/common/GlobalExceptionHandler.java
+++ b/src/main/java/com/yunhai/userbase/common/GlobalExceptionHandler.java
@@ -1,7 +1,9 @@
 package com.yunhai.userbase.common;
 
+import com.fasterxml.jackson.databind.JsonMappingException;
 import org.springframework.core.Ordered;
 import org.springframework.core.annotation.Order;
+import org.springframework.http.converter.HttpMessageNotReadableException;
 import org.springframework.validation.BindException;
 import org.springframework.validation.FieldError;
 import org.springframework.web.bind.MethodArgumentNotValidException;
@@ -13,6 +15,7 @@ import org.springframework.web.method.annotation.MethodArgumentTypeMismatchExcep
 import javax.validation.ConstraintViolation;
 import javax.validation.ConstraintViolationException;
 import java.util.LinkedHashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.stream.Collectors;
 
@@ -66,6 +69,27 @@ public class GlobalExceptionHandler {
         return paramError("参数类型不匹配: " + ex.getName());
     }
 
+    /**
+     * 请求体反序列化失败（Jackson 在进 Controller 前抛出，@Valid 兜不到）。典型如 birthday 等非空字段格式非法：
+     * 从异常最内层 {@link JsonMappingException} 的 path 取失败字段名，birthday 给点名提示，其余走通用文案。
+     * 空串/null 由 Jackson JSR-310 归一为 null、不抛，故不会误入此分支（满足「空不管」）。
+     */
+    @ExceptionHandler(HttpMessageNotReadableException.class)
+    public Map<String, Object> handleNotReadable(HttpMessageNotReadableException ex) {
+        String field = null;
+        Throwable cause = ex.getMostSpecificCause();
+        if (cause instanceof JsonMappingException) {
+            List<JsonMappingException.Reference> path = ((JsonMappingException) cause).getPath();
+            if (path != null && !path.isEmpty()) {
+                field = path.get(path.size() - 1).getFieldName();
+            }
+        }
+        if ("birthday".equals(field)) {
+            return paramError("birthday 字段类型需为yyyy-MM-dd");
+        }
+        return paramError("请求参数格式错误");
+    }
+
     private String fieldErrorsMessage(java.util.List<FieldError> fieldErrors) {
         if (fieldErrors == null || fieldErrors.isEmpty()) {
             return "参数校验失败";
diff --git a/src/test/java/com/yunhai/userbase/common/GlobalExceptionHandlerTest.java b/src/test/java/com/yunhai/userbase/common/GlobalExceptionHandlerTest.java
new file mode 100644
index 0000000..539fdd0
--- /dev/null
+++ b/src/test/java/com/yunhai/userbase/common/GlobalExceptionHandlerTest.java
@@ -0,0 +1,49 @@
+package com.yunhai.userbase.common;
+
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.databind.JsonMappingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.junit.jupiter.api.Test;
+import org.springframework.http.HttpInputMessage;
+import org.springframework.http.converter.HttpMessageNotReadableException;
+
+import java.util.Map;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+/**
+ * {@link GlobalExceptionHandler#handleNotReadable} 单测：请求体反序列化失败的友好提示。
+ * 纯单元（无 DB/Spring 上下文），直接构造异常断言返回信封。
+ */
+class GlobalExceptionHandlerTest {
+
+    private final GlobalExceptionHandler handler = new GlobalExceptionHandler();
+
+    @Test
+    void birthdayParseErrorReturnsFriendlyParamError() throws Exception {
+        JsonParser p = new ObjectMapper().createParser("{}");
+        JsonMappingException jme = JsonMappingException.from(p, "cannot deserialize LocalDate");
+        jme.prependPath(new JsonMappingException.Reference(null, "birthday"));
+        HttpMessageNotReadableException ex =
+                new HttpMessageNotReadableException("JSON parse error", jme, (HttpInputMessage) null);
+
+        Map<String, Object> body = handler.handleNotReadable(ex);
+
+        assertEquals(4, body.get("code"));
+        String msg = (String) body.get("msg");
+        assertTrue(msg.contains("birthday"), "msg 应点名 birthday 字段: " + msg);
+        assertTrue(msg.contains("yyyy-MM-dd"), "msg 应含期望格式 yyyy-MM-dd: " + msg);
+    }
+
+    @Test
+    void otherParseErrorReturnsGenericMessage() {
+        HttpMessageNotReadableException ex =
+                new HttpMessageNotReadableException("malformed JSON", (HttpInputMessage) null);
+
+        Map<String, Object> body = handler.handleNotReadable(ex);
+
+        assertEquals(4, body.get("code"));
+        assertEquals("请求参数格式错误", body.get("msg"));
+    }
+}