diff --git a/hrp/parameters.go b/hrp/parameters.go
index 9b263696..33631c2d 100644
--- a/hrp/parameters.go
+++ b/hrp/parameters.go
@@ -13,7 +13,7 @@ import (
 
 type TParamsConfig struct {
 	Strategy   iteratorStrategy            `json:"strategy,omitempty" yaml:"strategy,omitempty"`     // overall strategy
-	Strategies map[string]iteratorStrategy `json:"strategies,omitempty" yaml:"strategies,omitempty"` // map[string]string、string
+	Strategies map[string]iteratorStrategy `json:"strategies,omitempty" yaml:"strategies,omitempty"` // individual strategies for each parameters
 	Limit      int                         `json:"limit,omitempty" yaml:"limit,omitempty"`
 }
 
@@ -107,8 +107,8 @@ type ParametersIterator struct {
 	hasNext              bool       // cache query result
 	sequentialParameters Parameters // cartesian product for sequential parameters
 	randomParameterNames []string   // value is parameter names
-	limit                int
-	index                int
+	limit                int        // limit count for iteration
+	index                int        // current iteration index
 }
 
 // SetUnlimitedMode is used for load testing
@@ -145,11 +145,6 @@ func (iter *ParametersIterator) Next() map[string]interface{} {
 		return nil
 	}
 
-	if len(iter.data) == 0 {
-		iter.hasNext = false
-		return nil
-	}
-
 	var selectedParameters map[string]interface{}
 	if len(iter.sequentialParameters) == 0 {
 		selectedParameters = make(map[string]interface{})
diff --git a/hrp/parameters_test.go b/hrp/parameters_test.go
index f54516c3..e4bac50a 100644
--- a/hrp/parameters_test.go
+++ b/hrp/parameters_test.go
@@ -248,6 +248,59 @@ func TestInitParametersIteratorCount(t *testing.T) {
 	}
 }
 
+func TestInitParametersIteratorUnlimitedCount(t *testing.T) {
+	configParameters := map[string]interface{}{
+		"username-password": fmt.Sprintf("${parameterize(%s/account.csv)}", hrpExamplesDir), // 3
+		"user_agent":        []interface{}{"iOS/10.1", "iOS/10.2"},                          // 2
+		"app_version":       []interface{}{4.0},                                             // 1
+	}
+	testData := []struct {
+		cfg *TConfig
+	}{
+		// default, no parameters setting
+		{
+			&TConfig{
+				Parameters:        configParameters,
+				ParametersSetting: &TParamsConfig{},
+			},
+		},
+
+		// no parameters
+		// also will generate one empty item
+		{
+			&TConfig{
+				Parameters:        nil,
+				ParametersSetting: nil,
+			},
+		},
+	}
+	for _, data := range testData {
+		iterator, err := initParametersIterator(data.cfg)
+		if !assert.Nil(t, err) {
+			t.Fatal()
+		}
+		// set unlimited mode
+		iterator.SetUnlimitedMode()
+		if !assert.Equal(t, -1, iterator.limit) {
+			t.Fatal()
+		}
+
+		for i := 0; i < 100; i++ {
+			if !assert.True(t, iterator.HasNext()) {
+				t.Fatal()
+			}
+			iterator.Next() // consume next parameters
+		}
+		if !assert.Equal(t, 100, iterator.index) {
+			t.Fatal()
+		}
+		// should also have next
+		if !assert.True(t, iterator.HasNext()) {
+			t.Fatal()
+		}
+	}
+}
+
 func TestInitParametersIteratorContent(t *testing.T) {
 	configParameters := map[string]interface{}{
 		"username-password": fmt.Sprintf("${parameterize(%s/account.csv)}", hrpExamplesDir), // 3
diff --git a/hrp/session.go b/hrp/session.go
index 8172d2ab..05621d09 100644
--- a/hrp/session.go
+++ b/hrp/session.go
@@ -112,7 +112,7 @@ func (r *SessionRunner) MergeStepVariables(vars map[string]interface{}) (map[str
 // updateConfigVariables updates config variables with given variables.
 // this is used for data driven
 func (r *SessionRunner) updateConfigVariables(parameters map[string]interface{}) {
-	if parameters == nil {
+	if len(parameters) == 0 {
 		return
 	}