For the issue of resource opportunistic scheduling in Orthogonal Frequency Division Multiple Access (OFDMA) systems with multimedia services supported，a resource scheduling algorithm of Minimum Performance Guarantee (MPG) based on Quality of Service (QoS) constraints was proposed. On the Basement of the opportunistic scheduling idea which was used to maximize the total throughput of the system, this paper realized the fair subcarrieres allocation among the services and guaranteed the QoS constraints of the services by designning the parameter of subcarrieres scheduling acording to the QoS constraints of services, and by using the method which solve the maximal weighted bipartite matching problem in graph theory. The simulation results show that the proposed algorithm can availably increase the total throughput of the system under guaranteeing a minimum rate constraints of every services.