Alt+F8，新建一个宏，代码如下

Sub SelectAllTables()
 
    Dim tempTable As Table
 
    Application.ScreenUpdating = False
 
    '判断文档是否被保护
    If ActiveDocument.ProtectionType = wdAllowOnlyFormFields Then
        MsgBox "文档已保护，此时不能选中多个表格！"
        Exit Sub
    End If
    '删除所有可编辑的区域
    ActiveDocument.DeleteAllEditableRanges wdEditorEveryone
    '添加可编辑区域
    For Each tempTable In ActiveDocument.Tables
        tempTable.Range.Editors.Add wdEditorEveryone
    Next
    '选中所有可编辑区域
    ActiveDocument.SelectAllEditableRanges wdEditorEveryone
    '删除所有可编辑的区域
    ActiveDocument.DeleteAllEditableRanges wdEditorEveryone
 
    Application.ScreenUpdating = True
 
End Sub