There are many kinds of failure modes of cylinder,such as wearout failure,fracture failure.All these failure modes have a direct relationship with the stress level of key parts in cylinder.In order to analyze the failure mechanism of cylinder,with the two chamber air pressures of cylinder obtained by MATLAB/SIMULINK simulation as the input boundary conditions,a FEM model was constructed based on the ANSYS/LSDYNA to simulate the dynamic process of cylinder.The cylinder motion test rig was built,and the relevant data was collected by LABVIEW to verify the correctness of the theoretical model and finite element model.The post processing of the simulation results was carried out to analyze the stresses and determine the failure mechanisms.It is found that all parts of the cylinder are subjected to alternating stresses with dramatic amplitude changes,and the location of the maximum stresses are the contact point between wear ring and cylinder tube,the contact point between bush and piston rod,and the threaded connection between piston rod and piston.The main failure mode of parts like piston and piston rod is impact failure,and the main failure mode of parts like bush and wearing ring is the failure of wear deformation.