diff --git a/sheet.go b/sheet.go
index e02782a..935deac 100644
--- a/sheet.go
+++ b/sheet.go
@@ -317,14 +317,11 @@ func (f *File) SetSheetName(oldName, newName string) {
 // string.
 func (f *File) GetSheetName(index int) string {
 	wb := f.workbookReader()
-	if wb != nil {
-		for _, sheet := range wb.Sheets.Sheet {
-			if sheet.SheetID == index {
-				return sheet.Name
-			}
-		}
+	realIdx := index - 1 // sheets are 1 based index, but we're checking against an array
+	if wb == nil || realIdx < 0 || realIdx >= len(wb.Sheets.Sheet) {
+		return ""
 	}
-	return ""
+	return wb.Sheets.Sheet[realIdx].Name
 }
 
 // GetSheetIndex provides a function to get worksheet index of XLSX by given
@@ -357,8 +354,8 @@ func (f *File) GetSheetMap() map[int]string {
 	wb := f.workbookReader()
 	sheetMap := map[int]string{}
 	if wb != nil {
-		for _, sheet := range wb.Sheets.Sheet {
-			sheetMap[sheet.SheetID] = sheet.Name
+		for i, sheet := range wb.Sheets.Sheet {
+			sheetMap[i+1] = sheet.Name
 		}
 	}
 	return sheetMap
diff --git a/sheet_test.go b/sheet_test.go
index ef795ad..3baa084 100644
--- a/sheet_test.go
+++ b/sheet_test.go
@@ -225,3 +225,24 @@ func TestUngroupSheets(t *testing.T) {
 	}
 	assert.NoError(t, f.UngroupSheets())
 }
+
+func TestGetSheetName(t *testing.T) {
+	f, _ := excelize.OpenFile(filepath.Join("test", "Book1.xlsx"))
+	assert.Equal(t, "Sheet1", f.GetSheetName(1))
+	assert.Equal(t, "Sheet2", f.GetSheetName(2))
+	assert.Equal(t, "", f.GetSheetName(0))
+	assert.Equal(t, "", f.GetSheetName(3))
+}
+
+func TestGetSheetMap(t *testing.T) {
+	expectedMap := map[int]string{
+		1: "Sheet1",
+		2: "Sheet2",
+	}
+	f, _ := excelize.OpenFile(filepath.Join("test", "Book1.xlsx"))
+	sheetMap := f.GetSheetMap()
+	for idx, name := range sheetMap {
+		assert.Equal(t, expectedMap[idx], name)
+	}
+	assert.Equal(t, len(sheetMap), 2)
+}