In order to solve the problem of complicated operation process and difficult to meet the measurement accuracy requirements in the dynamic imbalance impulse test of recoilless gun, a new test device was designed. The velocity and displacement of the recoilless gun were measured by the low-damping slide and high-precision sensor, and the dynamic unbalance impulse of the recoilless gun was calculated according to the momentum principle. The test results show that the average test error of the system is 0.48%, and the system can be successfully applied to the dynamic unbalance impulse test of recoilless gun.