The performance of air traffic control system was evaluated by using Analytic Hierarchy Process (AHP). Firstly, the factors that can affect the performance of air traffic control system were analyzed and air traffic control system's performance guidelines and metrics suitable for the characteristics of China's military and civil aviation were established. Then the relative weight of these guidelines could be obtained by computing the judgment matrix that was constructed by experts. At last, the relative weight to the system performance could be got by recursively using probability multiplication methods. Finally the value of air traffic control system's performance equaled the liner weighted value of product between weights and their corresponding indicators of membership. According to the statistics conducted by the simulation, it is basically the same as the conclusions of experts, which shows it is reasonable to use AHP in the performance evaluation of air traffic control system.