Abstract: The 3D finite element model of 2024 aluminum alloy shot peening with a number of random projectiles was established using finite element analysis software ABAQUS. Firstly, the change characteristics of residual stress field under different number of projectiles were simulated; And then the influences of velocity and diameter of projectile on residual stress field were analyzed; At last, the simulation results were verified by experiment. The results show that the residual stress kept unchanged when the number of projectiles was more than 80. The depth of compressive residual stress layer, the value of compressive residual stress at every depths and the peark compressive residual stress increased remarkably with the increase of the velocity of projectile, but the depth of peak compressive residual stress changed little; With the increase of the diameter of projectile, the depth of compressive residual stress layer, compressive residual stress in depth below 0.1 mm, peak compressive resudual stress and its depth improved significantly, but compressive residual stress in the depth range of 0-0.1 mm changed little. The experimental results is closed to the simulated ones, this indicate that the simulation is correct.