The tail buffer device is the core device in the minimum take-off speed flight test.The key is the performance of the buffer,which depends on the design of the damping oil orifice.The type of damping oil orifice adopted was distributed variable oil orifice with constant diameter and variable distance.The parameters of oil orifice diameter were optimized by MSC.ADAMS and AMESim co-simulation.The results show that the optimized damping oil orifice has higher buffering efficiency,lower peak damping force and better performance.