diff --git a/docs/BUILTIN.md b/docs/BUILTIN.md
new file mode 100644
index 00000000..e90b0a04
--- /dev/null
+++ b/docs/BUILTIN.md
@@ -0,0 +1,44 @@
+# Builtin
+
+## Assertion Methods
+
+### Usage
+In "teststeps" of each json/yaml testcase, the "validate" part contains four fields: "check", "assert", "expect" and 
+"msg", when using assertion methods, method name should be put in "assert" field. The assertion result of "check" 
+element will be checked out using the regulation you put in "assert" field and compared with the element in "expect"
+field.
+
+### Method List
+
+- equals: assert the element to check equals the expected element.
+- equal: alias for equals.
+- greater_than: assert the element to check is greater than the expected element.
+- less_than: assert the element to check is less than the expected element.
+- greater_or_equals: assert the element to check is greater than or equal with the expected element.
+- less_or_equals: assert the element to check is less than or equal with the expected element.
+- not_equal: assert the element to check is not equal with the expected element.
+- contained_by: assert the expected element contains the element to check.
+- regex_match: assert the element to check matches the expected element using regex.
+- type_match: assert the element to check matches the expected element in type.
+- startswith: assert the element to check starts with the expected element.
+- endswith: assert the element to check ends with the expected element.
+- length_equals: assert the length of the element to check is equal with the expected element.
+- length_equal: alias for length_equals.
+- contains: assert the element to check contains the expected element.
+- string_equals: assert the string is equal with the expected string.
+
+## Common Functions
+
+### Usage
+The common functions are useful during the variables configuration, you can use "${FUNCTION_NAME}" to call the specific 
+function to define variables.
+
+### Function List
+- get_timestamp: get the thirteen-digit timestamp of current time. (call without argument)
+- sleep: sleep n seconds to simulate the thinking time. (call with one argument n)
+- gen_random_string: get the n-digit random string. (call with one argument n)
+- max: get the maximum of two numbers m and n. (call with two argument m and n)
+- md5: get the MD5 of the input string s. (call with one argument s)
+
+
+
diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index 4f2f8207..4959cea2 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 ## v0.3.1 (2021-12-30)
 
+- feat: add more plentiful response assertion methods
 - feat: set ulimit to 10240 before load testing
 - fix: concurrent map writes in load testing
 
diff --git a/examples/function_test.go b/examples/function_test.go
index cd2c2d98..44c8c590 100644
--- a/examples/function_test.go
+++ b/examples/function_test.go
@@ -19,14 +19,18 @@ func TestCaseCallFunction(t *testing.T) {
 		TestSteps: []hrp.IStep{
 			hrp.NewStep("get with params").
 				GET("/get").
-				WithParams(map[string]interface{}{"foo1": "${gen_random_string($n)}", "foo2": "${max($a, $b)}"}).
+				WithParams(map[string]interface{}{"foo1": "${gen_random_string($n)}", "foo2": "${max($a, $b)}", "foo3": "Foo3"}).
 				WithHeaders(map[string]string{"User-Agent": "HttpRunnerPlus"}).
 				Extract().
 				WithJmesPath("body.args.foo1", "varFoo1").
 				Validate().
 				AssertEqual("status_code", 200, "check status code").
 				AssertLengthEqual("body.args.foo1", 5, "check args foo1").
-				AssertEqual("body.args.foo2", "12.3", "check args foo2"), // notice: request params value will be converted to string
+				AssertEqual("body.args.foo2", "12.3", "check args foo2").
+				AssertTypeMatch("body.args.foo3", "str", "check args foo3 is type string").
+				AssertStringEqual("body.args.foo3", "foo3", "check args foo3 case-insensitivity").
+				AssertContains("body.args.foo3", "Foo", "check contains ").
+				AssertContainedBy("body.args.foo3", "this is Foo3 test", "check contained by"), // notice: request params value will be converted to string
 			hrp.NewStep("post json data with functions").
 				POST("/post").
 				WithHeaders(map[string]string{"User-Agent": "HttpRunnerPlus"}).
diff --git a/internal/builtin/assertion.go b/internal/builtin/assertion.go
index c995e26e..d59f6366 100644
--- a/internal/builtin/assertion.go
+++ b/internal/builtin/assertion.go
@@ -16,8 +16,9 @@ var Assertions = map[string]func(t assert.TestingT, expected interface{}, actual
 	"greater_or_equals": assert.GreaterOrEqual,
 	"less_or_equals":    assert.LessOrEqual,
 	"not_equal":         assert.NotEqual,
-	"contains":          assert.Contains,
+	"contained_by":  	 assert.Contains,
 	"regex_match":       assert.Regexp,
+	"type_match":        assert.IsType,
 	// custom assertions
 	"startswith":               StartsWith, // check if string starts with substring
 	"endswith":                 EndsWith,   // check if string ends with substring
@@ -27,6 +28,8 @@ var Assertions = map[string]func(t assert.TestingT, expected interface{}, actual
 	"length_less_or_equals":    LessOrEqualsLength,
 	"length_greater_than":      GreaterThanLength,
 	"length_greater_or_equals": GreaterOrEqualsLength,
+  "contains":                 Contains,
+	"string_equals":            EqualString,
 }
 
 func StartsWith(t assert.TestingT, expected, actual interface{}, msgAndArgs ...interface{}) bool {
@@ -149,6 +152,23 @@ func convertInt(value interface{}) (int, error) {
 	}
 }
 
+// Contains assert whether actual element contains expected element
+func Contains(t assert.TestingT, expected, actual interface{}, msgAndArgs ...interface{}) bool {
+	return assert.Contains(t, actual, expected, msgAndArgs)
+}
+
+func EqualString(t assert.TestingT, expected, actual interface{}, msgAndArgs ...interface{}) bool {
+	if !assert.IsType(t, "string", actual, msgAndArgs) {
+		return false
+	}
+	if !assert.IsType(t, "string", expected, msgAndArgs) {
+		return false
+	}
+	actualString := actual.(string)
+	expectedString := expected.(string)
+	return assert.True(t, strings.EqualFold(actualString, expectedString), msgAndArgs)
+}
+
 // getLen try to get length of object.
 // return (false, 0) if impossible.
 func getLen(x interface{}) (ok bool, length int) {
diff --git a/internal/builtin/function.go b/internal/builtin/function.go
index f4f7aaae..5554eaf6 100644
--- a/internal/builtin/function.go
+++ b/internal/builtin/function.go
@@ -19,7 +19,7 @@ var Functions = map[string]interface{}{
 	"sleep":             sleep,           // call with one argument
 	"gen_random_string": genRandomString, // call with one argument
 	"max":               math.Max,        // call with two arguments
-	"md5":               MD5,
+	"md5":               MD5,			        // call with one argument
 	"parameterize":      loadFromCSV,
 	"P":                 loadFromCSV,
 }
diff --git a/validate.go b/validate.go
index 9464ea1b..8e2e857b 100644
--- a/validate.go
+++ b/validate.go
@@ -101,6 +101,17 @@ func (s *StepRequestValidation) AssertContains(jmesPath string, expected interfa
 	return s
 }
 
+func (s *StepRequestValidation) AssertTypeMatch(jmesPath string, expected interface{}, msg string) *StepRequestValidation {
+	v := Validator{
+		Check:   jmesPath,
+		Assert:  "type_match",
+    Expect:  expected,
+		Message: msg,
+	}
+	s.step.Validators = append(s.step.Validators, v)
+	return s
+}
+
 func (s *StepRequestValidation) AssertRegexp(jmesPath string, expected interface{}, msg string) *StepRequestValidation {
 	v := Validator{
 		Check:   jmesPath,
@@ -145,6 +156,18 @@ func (s *StepRequestValidation) AssertLengthEqual(jmesPath string, expected inte
 	return s
 }
 
+
+func (s *StepRequestValidation) AssertContainedBy(jmesPath string, expected interface{}, msg string) *StepRequestValidation {
+	v := Validator{
+		Check:   jmesPath,
+		Assert:  "contained_by",
+    Expect:  expected,
+		Message: msg,
+	}
+	s.step.Validators = append(s.step.Validators, v)
+	return s
+}
+
 func (s *StepRequestValidation) AssertLengthLessThan(jmesPath string, expected interface{}, msg string) *StepRequestValidation {
 	v := Validator{
 		Check:   jmesPath,
@@ -156,6 +179,17 @@ func (s *StepRequestValidation) AssertLengthLessThan(jmesPath string, expected i
 	return s
 }
 
+func (s *StepRequestValidation) AssertStringEqual(jmesPath string, expected interface{}, msg string) *StepRequestValidation {
+	v := Validator{
+		Check:   jmesPath,
+		Assert:  "string_equals",
+    Expect:  expected,
+		Message: msg,
+	}
+	s.step.Validators = append(s.step.Validators, v)
+	return s
+}
+
 func (s *StepRequestValidation) AssertLengthLessOrEquals(jmesPath string, expected interface{}, msg string) *StepRequestValidation {
 	v := Validator{
 		Check:   jmesPath,