A method, a device and a system for combination of resource admission control are provided. The system includes the policy determination combination device and multiple bearer and transmission devices. The combination device combines functions and interfaces of two or multiple kinds of arbitrary policy determination devices in systems of different standards, and has multiple interfaces to be connected with the bearer and transmission devices, and selects the corresponding interface working protocol according to the type of bearer and transmission device. Multiple bearer and transmission devices are connected with the policy determination combination device by different interfaces. By setting policy determination combination device, the combination of policy determination devices is realized with a few changes to the current network. When there are multiple types of bearer and transmission devices in a management domain, the number of the policy determination devices can be efficiently reduced, and the cost of setting up the network and maintenance can be reduced. Also, it is propitious to collaborate and combine different standards and to improve speed of industrialization.