The work aims to study the formation and stress distribution of the surface residual stress field of the arc groove of 6061-T6 aluminum alloy specimen after ultrasonic impact treatment. By means of finite element analysis software, the residual stress field distribution of the arc groove is simulated by ultrasonic impact treatment, and the effect of different technological parameters on the residual stress value on the bottom surface of the arc groove is investigated by comparing the simulation results with the orthogonal process test. The results show that the ultrasonic impact treatment has formed a residual compressive stress layer with a thickness of about 0.35mm at the bottom of the arc groove, the residual stress first increased and then decreased along the depth direction, and the maximum residual stress value can reach about -362.5MPa. The process test is basically consistent with the influence trend of various process parameters on the residual stress value of the bottom surface of the groove obtained by the finite element simulation under the same condition, the residual stress value at the bottom of the arc groove increases with the increase of tool vibration amplitude, and decreases slightly with the increase of machining gap, while the change of workpiece movement velocity has little effect on the stress value.