To directly simulate different loading and unloading annular spring, taking certain type aircraft gatling gun as the research object, in the Matlab/Simulink software environment, a simulation model for the recoil buffer of annular spring with different stiffness is established, and compare it with simulation results constant stiffness. Research results show that changes in the unloading stiffness of the annular spring will not affect the simulation of the results of the maximum recoil displacement and the maximum recoil speed, but the changes in the unloading stiffness will increase the maximum forward displacement and the maximum forward speed.