In an authority management method for providing interoperability across different locations and networks, an identity information database and an authority information database are established. Biological image information is obtained from users and registered in the database or an associated database. Biometric image information and an access request of a user are obtained. If there is certain identity information matching the biometric image information of the user in the identity information database, information as to authority and extent of authority are certain identity information queried from the authority information database. The access request is determined to be allowed or not allowed according to the certain authority information. If the access request is to be granted, and allowed in respect of a desired activity, an operation instruction is generated accordingly. A system for administering such method and device applying method are also disclosed.