A network access authentication and authorization method includes the steps of: constructing an access and authorization request packet; constructing a certificate authentication request packet, constructing a certificate authentication response packet; constructing an access and authorization response packet; constructing an access and authorization acknowledgement packet. And an authorization key updating method includes the steps of: constructing an access and authorization request packet; constructing an access and authorization response packet; constructing an access and authorization acknowledgement packet. The invention resolves the security problem that a mobile terminal accesses a base station in the wideband wireless multimedia network, and realizes both bi-directional identity authentication of a mobile terminal and a base station and unidirectional identity authentication from a base station to a mobile terminal. The authorization key negotiation calculation is simple, and the key management is simply realized by using message acknowledgement manner. The invention is applied to the wired network and the wireless network, such as the wireless local area network, the wireless metropolitan area network, and the broadband wireless multimedia network etc.