diff --git a/core/src/main/java/cn/edu/tsinghua/iot/benchmark/conf/ConfigDescriptor.java b/core/src/main/java/cn/edu/tsinghua/iot/benchmark/conf/ConfigDescriptor.java
index f61889da4..e9bfb523c 100644
--- a/core/src/main/java/cn/edu/tsinghua/iot/benchmark/conf/ConfigDescriptor.java
+++ b/core/src/main/java/cn/edu/tsinghua/iot/benchmark/conf/ConfigDescriptor.java
@@ -174,7 +174,7 @@ private void loadProps() {
               throw new RuntimeException(
                   "The database "
                       + config.getDbConfig().getDB_SWITCH()
-                      + " can't use microsecond precision");
+                      + " can't use us/ns precision");
             }
             break;
           default: