原来是微软专家的代码在这：
http://www.microsoft.com/china/technet/community/scriptcenter/resources/hey060127.mspx
我改成了全自动式的，不需要手要修改域的adsi连接字符串了，代码：
On Error Resume Next
Set objRootDSE = GetObject("LDAP://rootDSE")
strDomain = ObjRootDSE.Get("defaultNamingContext")
Const ADS_SCOPE_SUBTREE = 2
Set objConnection = CreateObject("ADODB.Connection")
Set objCommand = CreateObject("ADODB.Command")
objConnection.Provider = "ADsDSOObject"
objConnection.Open "Active Directory Provider"
Set objCommand.ActiveConnection = objConnection
objCommand.Properties("Page Size") = 1000
objCommand.Properties("Searchscope") = ADS_SCOPE_SUBTREE
objCommand.CommandText = _
"SELECT Name FROM 'LDAP://" & strDomain & "' WHERE objectCategory='computer'"
Set objRecordSet = objCommand.Execute
Wscript.Echo objRecordSet.RecordCount