The invention discloses a novel bandwidth allocation algorithm supporting QoS. According to the algorithm, based on utility functions, a user demand factor and a service demand factor are considered comprehensively. According to the utility functions of all kinds of services in a network, influences on all kinds of service utilities by bandwidth are analyzed, so that weights are allocated to all kinds of services. According to a toll strategy made by an Internet provider, weights of all kinds of users are obtained when the bandwidth is allocated. By the utilization of an analytic hierarchy process, the service weights and the user weights are unified to be weights of specific users and specific services to serve as a basis when the network bandwidth is allocated. In order to provide better service quality, according to the method, the network load balancing problem is also researched so that influences on service quality caused by network load unbalancing can be reduced.