Abstract: Fast non-interference dynamic spectrum allocation is one of the key technologies to carry out cognitive radio.Aiming at the problem of existing algorithms based on graph coloring theory model costing too much time to allocate,combine parallel principle and interconnect component theory, a new method of parallel processing all connected branches is proposed. This method can be applied to each algorithm based on graph theory model,while ensuring original benefits,each algorithm can remarkably reduce the time cost in spectrum allocation process.An applying example for the method of parallel process connected branches is researched.The results show that the method is fast,active and adapting to the time-varying cognitive radio environment much better.