<%
      dim  sql,student_id,student_name,age,sex,in_time,homeplace,major
      student_id=Trim(Request.Form("student_id"))
      student_name=Trim(Request.Form("student_name"))
      sex=Trim(Request.Form("sex"))
      age=Trim(Request.Form("age"))
      in_time=Trim(Request.Form("in_time"))
      homeplace=Trim(Request.Form("homeplace"))
      major=Trim(Request.Form("major"))
      set urs=Server.CreateObject("ADODB.Recordset")
      sql="select student_id,student_name,sex,age,in_time,homeplace,major from student where student_name='"&student_name&"'"
      urs.open sql,conn,1,3
      if not rs.eof  then
             response.Write"<script> alert('此学生已存在.')</script>;history.back();"
             response.End
     else
            set rs="nothing"
            set rs=Server.CreateObject("ADODB.Recordset")
            sql="Selcet student_id,student_name,sex,age,in_time,homeplace,major  from student"
            urs.open sql,conn,1,3// 第 12 行
            urs.addnew
            urs("student_id")=student_id
            urs("student_name")=student_name
            urs("sex")=sex
            urs("in_time")=in_time
            urs("homeplace")=homeplace
            urs("major")=major
            urs.update
            urs.close
            set urs=nothing
     end if
 
  set urs=nothing
  response.Write "<script language=javascript>{window.alert('记录添加成功!请点击“确定”');window.location.href='add_student.asp';}</script>"                        
%>
ADODB.Recordset (0x800A0BB9)
参数类型不正确，或不在可以接受的范围之内，或与其他参数冲突。
/biyesheji/admin/save.asp, 第 12 行

麻烦大家看看为什么出错了,谢谢

set rs=Server.CreateObject("ADODB.Recordset")
            sql="Selcet student_id,student_name,sex,age,in_time,homeplace,major  from student"
            urs.open sql,conn,1,3// 第 12 行
注意看2个红色字体对象一样吗？你建立的是rs对象，而操作上的却是urs

也许你会说上面已经建立了urs，但是2个查询根本不是同一回事！
建议下面的全部改为使用rs：
            set rs=Server.CreateObject("ADODB.Recordset")
            sql="Selcet * from student"
            rs.open sql,conn,1,3// 第 12 行
            rs.addnew
            rs("student_id")=student_id
            rs("student_name")=student_name
            rs("sex")=sex
            rs("in_time")=in_time
            rs("homeplace")=homeplace
            rs("major")=major
            rs.update
            rs.close
            set rs=nothing
并确保每个变量或字段对应数据库里都有值存在！

你前面的是urs,、可后面却是：（注意红色标出的）
             if not rs.eof  then
             response.Write"<script> alert('此学生已存在.')</script>;history.back();"
             response.End

还有这里：  else
            set rs="nothing"
            set rs=Server.CreateObject("ADODB.Recordset")
            sql="Selcet student_id,student_name,sex,age,in_time,homeplace,major  from student"