Abstract: In view of the problem that the traditional detection methods of underwater breathing apparatus are inefficient and unsafe, a performance detection system of underwater breathing apparatus is designed.The system simulates the deep sea environment with compression chambers, and simulates the function of human lung respiration with breathing machine. what’s more, the use of breathing apparatus is simulated by adjusting the pressure of the compression chambers. By using analysis of gas content by analyzers, outlet pressure of pressure relief valve measured by pressure sensor and respiratory resistance, etc., various data on the performance of breathing apparatus can be detected in all directions. The test results showed that the system meets the design requirements and can effectively detect the performance of underwater breathing apparatus.