ABAQUS software was used to simulate the ultrasonic impact strengthening process, analyze the formation process of residual stress field and the distribution regular of residual stress in the surface layer,single factor test was used to study the influence regular of the output current and impedance threshold of the main process parameters on the residual stress, the residual stress size and distribution were measured and analyzed by XRD-ray residual stress tester, compared with the finite element analysis results,verify the rationality of finite element simulation. After ultrasonic impact strengthening of 7075 aluminum alloy by the amplitude of 10μm and the frequency of 28 kHz, software simulation shows the results: the layer of residual stress is about 100μm and the maximum residual stress is﹣574 MPa,it appears at the surface depth of 60 μm,experiment shows the results: the layer of residual stress is about 120 μm and the maximum residual stress is﹣330 MPa, it appears at the surface depth of 40μm, the simulation results are larger than the experimental results, but the trend is consistent. In the constant current source ultrasonic impact strengthening, the output current and impedance threshold have influence on the magnitude and distribution of residual stress, the influence of impedance threshold is closer to the amplitude in simulation; in the same output current, the increase of impedance threshold can obtain large residual stress in the aluminum alloy shallow layer, When the impedance threshold sustain the same value, the larger compressive residual stress can be obtained by increasing the output current. The microstructure analysis is a direct reaction to the surface strengthening.