diff --git a/a8/xtimer.cc b/a8/xtimer.cc
index f668d64..7dba959 100644
--- a/a8/xtimer.cc
+++ b/a8/xtimer.cc
@@ -254,9 +254,12 @@ namespace a8
         }
     }
 
-    a8::XParams& XTimer::GetTimerXParams(xtimer_list* timer)
+    a8::XParams* XTimer::MutableParams(xtimer_list* timer)
     {
-        return timer->param;
+        if (!timer) {
+            abort();
+        }
+        return &timer->param;
     }
 
     xtimer_list* XTimer::GetRunningTimer()
diff --git a/a8/xtimer.h b/a8/xtimer.h
index e63d710..fe5f8c6 100644
--- a/a8/xtimer.h
+++ b/a8/xtimer.h
@@ -40,7 +40,7 @@ namespace a8
         void DeleteTimer(xtimer_list* timer);
         //通过关联的list_head获取定时器对象
         xtimer_list* GetTimerByAttach(list_head* attach_entry);
-        a8::XParams& GetTimerXParams(xtimer_list* timer);
+        a8::XParams* MutableParams(xtimer_list* timer);
         xtimer_list* GetRunningTimer();
 
     private: