A system of multiple services with guaranteed QoS requires resource allocation. A novel algorithm on bandwidth allocation together with associate class-unit application model is proposed in this article. Bandwidth is allocated to flows in unit of class due to different QoS-bandwidth functions. Applications within one class achieve the same bandwidth and the allocation among classes based on QoS-Based MAX-MIN fairness. Simulations confirm that the proposed scheme simplifies the calculation of the so-called host station, and flows achieve satisfying QoS based on QoS-bandwidth functions.