Aircraft collision avoidance system is an important part of ensuring aviation safety. ADS-B (Automatic Dependent Surveillance-Broadcast) technology, as an advanced aeronautical communication and surveillance technology, offers the possibility of optimizing the application of aircraft collision avoidance system by providing more accurate and timely position and status information. This study adopts a comprehensive analysis and system design approach. Explaining the working scope of ADS-B, the collision avoidance characteristics of general aviation aircraft, constructing a three-level collision avoidance system of emergency collision avoidance, general collision avoidance and advance collision avoidance, and analyzing the division of the area in the collision avoidance system, and proposing the collision avoidance processing flow.