The current aircraft collision avoidance system is made up of TCAS and the two independent subsystems and their accessory equipments of mode S transponder. This structure causes great waste of space in the aircraft and higher cost of design. At the same time, large volume also limits the application of TCAS in military areas. To solve this problem, the concept of integration TCAS system is introduced, the communication coding and decoding in the integrated system is designed and the experimental results are given.