1. 在项目中添加引用msjro.dll（c:\program files\comm files\System\ado\msjro.dll）；

2. 引用 using JRO;

3.实现

        Dim Path1 As String, Path2 As String, DbConn1 As String, DbConn2 As String

        Path1 = Server.MapPath("aa.mdb") '原数据库
        Path2 = Server.MapPath("db2.mdb") '压缩后的数据库
        DbConn1 = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + Path1
        DbConn2 = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + Path2

        Dim DatabaseEngin As JetEngine = New JetEngine()
        DatabaseEngin.CompactDatabase(DbConn1, DbConn2) '压缩

        File.Copy(Path2, Path1, True) '将压缩后的数据库覆盖原数据库
        File.Delete(Path2) '删除压缩后的数据库