您好！
如果是SharePoint 组的话，您可以参考下面的链接：
SharePoint Management PowerShell scripts
http://sharepointpsscripts.codeplex.com/Release/ProjectReleases.aspx?ReleaseId=21699#DownloadId=77312
SPWeb.AllUsers Property (Microsoft.SharePoint)
http://msdn.microsoft.com/en-us/library/microsoft.sharepoint.spweb.allusers.aspx
http://social.msdn.microsoft.com/Forums/en-US/sharepointdevelopment/thread/49701a4d-7e7a-42a5-83b8-e3f15069c25b/
如果是Active Directory 组的话，请参考下面的链接：
How to Get All User Members From Nested Security Groups in Active Directory Using .NET and C#
http://blogs.msdn.com/securitytools/archive/2009/07/31/how-to-get-all-user-members-from-nested-security-groups-in-active-directory-using-net-and-c.aspx
Rock Wang 望正茂
