Abstract: Four layers shot peening model of 18CrNiMo7-6 gear steel was built by ANSYS10.0 software, the residual stress distribution of gear steel after shot peening by shot with different strength under the condition of considering elasticoplastic deformation of shots, and experiment verification was performed. The results show that a residual compressive stress layer with thickness of 0.4 mm and maximum compressive stress of 800-1 200 MPa appeared on gear steel surface, and the distance from the position appearing maximum residual compressive stress to surface was 0.12 mm. The residual compressive stress increased with the increase of the strength of shots, and the experimental residual stress distribution coincided with the simulated ones for gear steel after shot peening.