采用VBA操作
打开word，Alt+F11进入VBA界面，插入>模块，将下面代码帖进去，按F5即可
Sub doc2docx() 'doc文件转docx文件
Dim myDialog As FileDialog, oFile As Variant
Set myDialog = Application.FileDialog(msoFileDialogFilePicker)
With myDialog
.Filters.Clear '清除所有文件筛选器中的项目
.Filters.Add "所有 WORD97-2003 文件", "*.doc", 1 '增加筛选器的项目为所有WORD97-2003文件
.AllowMultiSelect = True '允许多项选择
If .Show = -1 Then '确定
For Each oFile In .SelectedItems '在所有选取项目中循环
With Documents.Open(oFile)
.SaveAs FileName:=Replace(oFile, "doc", "docx"), FileFormat:=12
.Close
End With
Next
End If
End With
End Sub
方法来源：http://club.excelhome.net/thread-838847-1-1.html
类似的docx转doc
Sub docx2doc() 'docx文件转doc文件
Dim myDialog As FileDialog, oFile As Variant
Set myDialog = Application.FileDialog(msoFileDialogFilePicker)
With myDialog
.Filters.Clear '清除所有文件筛选器中的项目
.Filters.Add "所有 WORD2007 文件", "*.docx", 1 '增加筛选器的项目为所有WORD2007文件
.AllowMultiSelect = True '允许多项选择
If .Show = -1 Then '确定
For Each oFile In .SelectedItems '在所有选取项目中循环
With Documents.Open(oFile)
.SaveAs FileName:=Replace(oFile, "docx", "doc"), FileFormat:=0
.Close
End With
Next
End If
End With
End Sub
