A dynamic spectrum division process based on graph theory is proposed in the scenario of multiauthorized user satellite cognitive communication between satellite and ground networks. First of all, the graph theory model is introduced. Secondly, this paper analyzes the cognitive authorized users under the condition of satellite communication scenarios. According to the cognitive users perceive, the paper makes use of the graph theory model with the authorized users perception of the matrix, and uses the throughput of the cognitive users and the authorized user of spectrum idle state parameters such as communication by iteration to get the final spectrum access matrix and completed many authorized users under the condition of spectrum. The simulation results show that the algorithm can divide cognitive users into the spectrum of authorized users with the highest revenue within the range of cognitive users perception ability.