数据库一般都有密码保护，但地理数据库没有。尝试用ArcGIS打开由Access创建的mdb数据库也无效。
官方也回答了这个问题
Question
Can I use or set passwords on a personal geodatabase?
Answer
No, while the underlying(潜在的) .mdb file supports the use of passwords, the geodatabase and ArcGIS do not. Microsoft Access .mdb files that are password protected cannot be opened in ArcGIS, nor can password protected personal geodatabases be created in ArcGIS.
If the intention(意图) is to restrict users from accessing the personal geodatabase, setting the appropriate(适当的) user level permissions on the folder is recommended. For more information on setting different permissions for different users accessing a personal geodatabase, see the following ESRI Knowledge Base article in the Related Information below.
当然了，也不是不能连接。但始终是连的MS的mdb，不是真正的个人地理数据库，存储图形操作也就不方便了。
参考：
<a href="http://support.esri.com/em/knowledgebase/techarticles/detail/34871">http://support.esri.com/em/knowledgebase/techarticles/detail/34871</a>
<a href="http://support.esri.com/en/knowledgebase/techarticles/detail/25325">http://support.esri.com/en/knowledgebase/techarticles/detail/25325</a>
<a href="http://help.arcgis.com/zh-CN/Arcgisdesktop/10.0/Help/index.html#//005s00000023000000">http://help.arcgis.com/zh-CN/Arcgisdesktop/10.0/Help/index.html#//005s00000023000000</a>
<a href="http://forums.esri.com/Thread.asp?c=93&f=985&t=207927">http://forums.esri.com/Thread.asp?c=93&f=985&t=207927</a>