The invention relates to a multi-net cooperative transmission resource distribution system in heterogeneous wireless environment and a method. The network side of the system comprises a service flow division unit and a service control unit, wherein the service flow division unit divides one service into a plurality of service sub flows according to the network carrying capability and the constriction conditions between different networks, the service control unit is used for processing a plurality of service sub flows and transmit the service sub flows to the terminal side through different wireless access networks. The terminal side comprises a consulting unit which identifies the service sub flows received by the equipment terminal and transfers the service sub flows to corresponding destination equipment terminals. The system and the method of the invention fully utilize the transmission capability of each wireless access network in the heterogeneous wireless environment, and divide the service into a plurality of sub flows to be transmitted on different networks, so single-mode terminals only supporting one network can support various kinds of services, resources of different networks can be fully utilized, and the load balance between different networks can be realized. Thereby, the system performances are optimized.