diff --git a/src/DataTypes/IDataType.h b/src/DataTypes/IDataType.h
index cb9fc7f122c..dba5bc3f5a9 100644
--- a/src/DataTypes/IDataType.h
+++ b/src/DataTypes/IDataType.h
@@ -597,6 +597,7 @@ inline bool isEnum(const DataTypePtr & data_type) { return WhichDataType(data_ty
 inline bool isDecimal(const DataTypePtr & data_type) { return WhichDataType(data_type).isDecimal(); }
 inline bool isTuple(const DataTypePtr & data_type) { return WhichDataType(data_type).isTuple(); }
 inline bool isArray(const DataTypePtr & data_type) { return WhichDataType(data_type).isArray(); }
+inline bool isMap(const DataTypePtr & data_type) {return WhichDataType(data_type).isMap(); }
 
 template <typename T>
 inline bool isUInt8(const T & data_type)
diff --git a/src/Functions/FunctionStringOrArrayToT.h b/src/Functions/FunctionStringOrArrayToT.h
index 6330d8f90d6..2108fa7e8b6 100644
--- a/src/Functions/FunctionStringOrArrayToT.h
+++ b/src/Functions/FunctionStringOrArrayToT.h
@@ -7,6 +7,7 @@
 #include <Columns/ColumnString.h>
 #include <Columns/ColumnFixedString.h>
 #include <Columns/ColumnArray.h>
+#include <Columns/ColumnMap.h>
 
 
 namespace DB
@@ -42,7 +43,7 @@ public:
     DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
     {
         if (!isStringOrFixedString(arguments[0])
-            && !isArray(arguments[0]))
+            && !isArray(arguments[0]) && !isMap(arguments[0]))
             throw Exception("Illegal type " + arguments[0]->getName() + " of argument of function " + getName(), ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
 
         return std::make_shared<DataTypeNumber<ResultType>>();
@@ -93,6 +94,22 @@ public:
 
             return col_res;
         }
+        else if (const ColumnMap* col_map = checkAndGetColumn<ColumnMap>(column.get()))
+        {
+            // only function length is implemented for ColumnMap
+            // TODO implemented other functions which use FunctionStringOrArrayToT
+            if (getName() != "length")
+                throw Exception("Illegal column " + arguments[0].column->getName() + " of argument of function " + getName(),
+                    ErrorCodes::ILLEGAL_COLUMN);
+
+            auto col_res = ColumnVector<ResultType>::create();
+            typename ColumnVector<ResultType>::Container & vec_res = col_res->getData();
+            vec_res.resize(col_map->size());
+            const auto & col_nested = col_map->getNestedColumn();
+
+            Impl::array(col_nested.getOffsets(), vec_res);
+            return col_res;
+        }
         else
             throw Exception("Illegal column " + arguments[0].column->getName() + " of argument of function " + getName(),
                 ErrorCodes::ILLEGAL_COLUMN);
diff --git a/tests/queries/0_stateless/01592_length_map.reference b/tests/queries/0_stateless/01592_length_map.reference
new file mode 100644
index 00000000000..51993f072d5
--- /dev/null
+++ b/tests/queries/0_stateless/01592_length_map.reference
@@ -0,0 +1,2 @@
+2
+2
diff --git a/tests/queries/0_stateless/01592_length_map.sql b/tests/queries/0_stateless/01592_length_map.sql
new file mode 100644
index 00000000000..4f2b0737d82
--- /dev/null
+++ b/tests/queries/0_stateless/01592_length_map.sql
@@ -0,0 +1,6 @@
+set allow_experimental_map_type = 1;
+
+drop table if exists table_map;
+create table table_map (a Map(String, String)) engine = Memory;
+insert into table_map values ({'name':'zhangsan', 'gender':'male'}), ({'name':'lisi', 'gender':'female'});
+select length(a) from table_map;