diff --git a/collector/src/main/java/org/dromara/hertzbeat/collector/collect/mongodb/MongodbSingleCollectImpl.java b/collector/src/main/java/org/dromara/hertzbeat/collector/collect/mongodb/MongodbSingleCollectImpl.java
index cd4d5436a85..4751f1c98ef 100644
--- a/collector/src/main/java/org/dromara/hertzbeat/collector/collect/mongodb/MongodbSingleCollectImpl.java
+++ b/collector/src/main/java/org/dromara/hertzbeat/collector/collect/mongodb/MongodbSingleCollectImpl.java
@@ -112,6 +112,9 @@ public void collect(CollectRep.MetricsData.Builder builder, long appId, String a
                     document = (Document) document.get(metricsParts[i]);
                 }
             }
+            if (document == null) {
+                throw new RuntimeException("the document get from command " + metrics.getMongodb().getCommand()  + " is null.");
+            }
             fillBuilder(metrics, valueRowBuilder, document);
             builder.addValues(valueRowBuilder.build());
         } catch (MongoServerUnavailableException | MongoTimeoutException unavailableException) {
@@ -137,7 +140,7 @@ public String supportProtocol() {
     private void fillBuilder(Metrics metrics, CollectRep.ValueRow.Builder valueRowBuilder, Document document) {
         metrics.getAliasFields().forEach(it -> {
             if (document.containsKey(it)) {
-                Object fieldValue =document.get(it);
+                Object fieldValue = document.get(it);
                 if (fieldValue == null) {
                     valueRowBuilder.addColumns(CommonConstants.NULL_VALUE);
                 } else {