diff --git a/internal/default.go b/internal/default.go
index 4f48e7f..c0c554b 100644
--- a/internal/default.go
+++ b/internal/default.go
@@ -37,6 +37,9 @@ var (
 	// DefaultNowFunc is the default now function for all logger instances.
 	DefaultNowFunc = time.Now
 
+	// DefaultTimeFormat is the default time format for all logger instances.
+	DefaultTimeFormat = time.RFC3339
+
 	// ErrorWriter is used to output logger internal error messages.
 	ErrorWriter io.Writer = os.Stderr
 )
diff --git a/log.go b/log.go
index 713168a..8bf8a24 100644
--- a/log.go
+++ b/log.go
@@ -175,28 +175,30 @@ type Log interface {
 // The core type defines the collection of shared attributes within the log,
 // and each independent Logger shares the same core instance.
 type core struct {
-	name      string
-	level     Level
-	formatter Formatter
-	writer    io.Writer
-	pool      sync.Pool
-	hooks     HookBag
-	nowFunc   func() time.Time
-	exitFunc  func(int)
-	panicFunc func(string)
+	name       string
+	level      Level
+	formatter  Formatter
+	writer     io.Writer
+	pool       sync.Pool
+	hooks      HookBag
+	timeFormat string
+	nowFunc    func() time.Time
+	exitFunc   func(int)
+	panicFunc  func(string)
 }
 
 // Create a new core instance and bind the logger name.
 func newCore(name string) *core {
 	return &core{
-		name:      name,
-		level:     TraceLevel,
-		writer:    os.Stdout,
-		pool:      sync.Pool{New: func() interface{} { return new(logEntity) }},
-		hooks:     NewHookBag(),
-		nowFunc:   internal.DefaultNowFunc,
-		exitFunc:  internal.DefaultExitFunc,
-		panicFunc: internal.DefaultPanicFunc,
+		name:       name,
+		level:      TraceLevel,
+		writer:     os.Stdout,
+		pool:       sync.Pool{New: func() interface{} { return new(logEntity) }},
+		hooks:      NewHookBag(),
+		timeFormat: internal.DefaultTimeFormat,
+		nowFunc:    internal.DefaultNowFunc,
+		exitFunc:   internal.DefaultExitFunc,
+		panicFunc:  internal.DefaultPanicFunc,
 	}
 }
 
@@ -287,7 +289,7 @@ func (o *log) log(level Level, message string) {
 		}
 		err = json.NewEncoder(&entity.buffer).Encode(map[string]interface{}{
 			"name":    entity.name,
-			"time":    entity.time.Format(time.RFC3339),
+			"time":    entity.time.Format(o.core.timeFormat),
 			"level":   level.String(),
 			"message": message,
 			"fields":  fields,
diff --git a/logger.go b/logger.go
index 68ec008..7d880af 100644
--- a/logger.go
+++ b/logger.go
@@ -56,6 +56,10 @@ type Logger interface {
 	// If the given log formatter is nil, we will record the log in JSON format.
 	SetFormatter(Formatter) Logger
 
+	// SetDefaultTimeFormat sets the default log time format for the current logger.
+	// If the given time format is empty string, internal.DefaultTimeFormat is used.
+	SetDefaultTimeFormat(string) Logger
+
 	// AddHook adds the given log hook to the current logger.
 	AddHook(Hook) Logger
 
@@ -140,6 +144,17 @@ func (o *logger) SetFormatter(formatter Formatter) Logger {
 	return o
 }
 
+// SetDefaultTimeFormat sets the default log time format for the current logger.
+// If the given time format is empty string, internal.DefaultTimeFormat is used.
+func (o *logger) SetDefaultTimeFormat(format string) Logger {
+	if format == "" {
+		o.core.timeFormat = internal.DefaultTimeFormat
+	} else {
+		o.core.timeFormat = format
+	}
+	return o
+}
+
 // AddHook adds the given log hook to the current logger.
 func (o *logger) AddHook(hook Hook) Logger {
 	o.core.hooks.Add(hook)
diff --git a/logger_test.go b/logger_test.go
index a942d80..1134f1b 100644
--- a/logger_test.go
+++ b/logger_test.go
@@ -117,6 +117,13 @@ func TestLogger_SetFormatter(t *testing.T) {
 	}
 }
 
+func TestLogger_SetDefaultTimeFormat(t *testing.T) {
+	o := New("test")
+	if o.SetDefaultTimeFormat("2006-01-02 15:04:05") == nil {
+		t.Fatal("Logger.SetDefaultTimeFormat(): nil")
+	}
+}
+
 func TestLogger_Log(t *testing.T) {
 	w := new(bytes.Buffer)
 	o := New("test")