Because of the problem that the existing fixed spectrum allocation method of HF radio access to network cannot satisfy the new requirement of intelligent frequency hopping technology, the communication demand of HF radio access to network based on intelligent frequency hopping was analyzed, and the strategy and algorithm of dynamic spectrum allocation in intelligent frequency hopping HF radio access to network were proposed. Firstly, mobile users and base stations were regarded as a subnet, then the subnet of spectrum allocation model was modeled as spectrum allocation model by using graph coloring theory. Finally, allocation strategy and algorithm were put forward combined with communication demand to complete spectrum allocation. Simulation results show that the proposed strategy and algorithm can effectively solve application problem of intelligent frequency hopping technology in HF radio access to network. Compared with fixed frequency communication of fixed spectrum allocation method, dynamic spectrum allocation can obviously increase network benefits, subnet satisfaction, network fairness, the number of users and spectrum efficiency, and reduce the mutual interference ratio at the same time.