diff --git a/wandun/src/main/cpp/collect.c b/wandun/src/main/cpp/collect.c
index 0bbad4f..bddbb4b 100644
--- a/wandun/src/main/cpp/collect.c
+++ b/wandun/src/main/cpp/collect.c
@@ -433,7 +433,7 @@ void collect_mem_info(JNIEnv *env, cJSON *json) {
         u_long ram_total = si.totalram * si.mem_unit;
         u_long ram_free = si.freeram * si.mem_unit;
         char ram_buf[32] =  {0};
-        snprintf(ram_buf, 31, "lu, %lu", ram_total, ram_free);
+        snprintf(ram_buf, 31, "%lu, %lu", ram_total, ram_free);
         cJSON_AddStringToObject(item, "ram", ram_buf);
     }