A network 
authentication, 
authorization and accounting 
system and a method thereof, wherein said 
system comprises: a subscriber device, via which a subscriber is connected with the network; an access 
server, connected with the subscriber device and designed to enable the subscriber device to access the network; an AAA 
server, connected with the access 
server and designed to collaborate with the access server to accomplish 
authentication, 
authorization, and accounting for the subscriber accessing the network; a service server, connected with the access server, designed to provide specific services, to exchange 
authentication and 
authorization information with the AAA server, and to interact with the subscriber device to provide the service; a service accounting server, connected with the service server, designed to collaborate with the service server to accomplish accounting for 
service resource use of the subscriber, and to send the accounting data to the AAA server. Accordingly, the present invention also discloses a network authentication, authorization and 
accounting method. The present invention enables a subscriber to access different types of services with only the subscriber identification information (user name and 
password) through a single identity authentication process, and supports centralized accounting.