我来解决！！！
Dim objexcelApp

Set objexcelApp=CreateObject("excel.application")

objexcelApp.visible=True



objexcelapp.workbooks.open"e:\\zzj\excelexample.xls"

objexcelapp.cells(4,3).value="aaa"

objexcelapp.activeworkbooks.save

objexcelapp.workbooks.close

objexcelapp.quit

Set objexcelapp=nothing

此代码在wincc 6.0 下测试通过。