Abstract: Kinetic impact is considered an effective way to deflect potentially hazardous asteroids from a collision with Earth. To study the effect of impact velocity on the momentum transfer coefficient, 6 mm aluminum projectile was used to impact the basalt target at 2-4 km/s. By comparing the computation results of aluminum sphere impact on basalt with the experimental results, the correctness of the calculation and the statistical method of momentum transfer coefficient was verified. The simulation results show that the mass and velocity distributions of projectiles at different impact velocities were almost the same. The greater the impact velocity, the greater the cumulative mass of projectiles. Combing with the experimental and numerical simulation results, the momentum transfer coefficient similarity law of kinetic impacting asteroids was obtained. The momentum enhancement coefficient of the dense asteroid increases with the increased of the impact velocity to the power of 0.65. The momentum transfer similarity law can provide data support for the kinetic impact deflection of asteroids.