Abstract: The gas distribution mechanism affects the engine's air exchange process, which is directly related to whether the engine can give full play to its own performance. In order to improve the working performance of the gas distribution mechanism, the relationship between its working process and each parameter is analyzed. In this paper, based on the camshaft upward-mounted air distribution mechanism, a dynamic model of two-degree-of-freedom vibration system with elastic constraints is established, and the differential equations of the motion process are constructed through combining with the D'Alembert's principle and MATLAB software, and then computer numerical simulation is carried out so as to obtain the complex dynamic behavior of the system. It can be seen through the theoretical derivation and numerical simulation that with the change of paremeters, there are multiple paths from periodic motion to chaotic transitions in the working process of the air distribution mechanism. Finally, the relationship between the optimal parameter values and the working process of the gas distribution mechanism is determined, which provides some reference for the design optimization of the gas distribution mechanism.