Abstract: Three different shot peening processes(dry shot peening, dry shot peening followed by wet shot peening and wet shot peening) were used to strengthen the surface of 1Cr11Ni2W2MoV steel nut. The effects of shot peening process on the residual stress, roughness and microstructure of nut surface were compared. The results show that the residual compressive stress on the nut surface after wet shot peening was the largest, and the maximum residual compressive stress located at the large arc section, reaching 550 MPa; the surface roughness R_a was the smallest with the range of 0.75-0.85 μm. After dry shot peening, the surface residual compressive stress of nut was the smallest, and the surface roughness R_a was the largest ranging from 2.5-3.2 μm. After shot peening, the outer grains of nut was broken and refined obviously, while the grains of the center did not change obviously. After wet shot peening and dry shot peening followed by wet shot peening, 0.15 and 0.25 mm depth residual stress layers were formed on nut surface, respectively. The suitable process for strengthening the surface of 1Cr11Ni2W2MoV steel nut was dry shot peening followed by wet shot peening.