当然要用到 sqldmo 来做这个工作
找到 sqldmo.dll这个文件
C:\Program Files\Microsoft SQL Server\80\Tools\Binn\sqldmo.dll
用.Net框架提供的工具转成受托管代码
tlbimp sqldmo.dll /out: c:\SQLDMO.dll

这样就可以如下例所示引用了
<%@ Import Namespace="SQLDMO" %>
具体代码如下

    Dim oBackup As SQLDMO.Backup = new SQLDMO.BackupClass()
    Dim oSQLServer As SQLDMO.SQLServer = new SQLDMO.SQLServerClass()
    oSQLServer.LoginSecure = false
    oSQLServer.Connect("localhost", "sa", "密码")
    oBackup.Action = SQLDMO.SQLDMO_BACKUP_TYPE.SQLDMOBackup_Database
    oBackup.Database = "数据库"
    oBackup.Files = "D:\Jnszf.bak"
    oBackup.BackupSetName = "数据库"
    oBackup.BackupSetDescription = "数据库备份"
    oBackup.Initialize = true
    oBackup.SQLBackup(oSQLServer)
    oSQLServer.DisConnect()
    Dim fi As System.IO.FileInfo = new System.IO.FileInfo("D:\Jnszf.bak")