Authentication method, server and system

The invention provides an authentication method, an authentication server and an authentication system. The authentication method is used for realizing the linkage authentication of 802.1X and a Windows active directory (AD) domain, and comprises that: an 802.1X authentication server receives an authentication request carrying a username and a blank password of a user from the user; the 802.1X authentication server transmits the username and the blank password to a Windows AD domain server which verifies the username and the blank password; after the username and the blank password pass the verification, the 802.1X authentication server transmits a query request carrying the username to the Windows AD domain server; the Windows AD domain server judges whether the username belongs to an authorized user or not; and if the username belongs to the authorized user, the linkage authentication is successfully finished.