diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/rules/expression/rules/FoldConstantRuleOnBE.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/rules/expression/rules/FoldConstantRuleOnBE.java
index 3c2f0d546dd04a..e0e19bd19e2b06 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/nereids/rules/expression/rules/FoldConstantRuleOnBE.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/nereids/rules/expression/rules/FoldConstantRuleOnBE.java
@@ -215,6 +215,11 @@ private static void collectConst(Expression expr, Map<String, Expression> constM
                 LOG.warn("expression {} translate to legacy expr failed. ", expr, e);
                 return;
             }
+            if (staleExpr == null) {
+                // just return, it's a fail-safe
+                LOG.warn("expression {} translate to legacy expr failed. ", expr);
+                return;
+            }
             tExprMap.put(id, staleExpr.treeToThrift());
         } else {
             for (int i = 0; i < expr.children().size(); i++) {