Abstract: Soil nailing is an economic and convenient method for slope stabilization and excavation support. In engineering practice,geotechnical practitioners only take tensile forces into consideration during design,regardless of shear forces. To investigate the contribution of the shear effect of soil nails to the stability of clay slopes,this paper draws attention to the effect of shear forces on the factor of safety and potential failure surface,using Geo-studio's slope/W mode,and concludes some suggestions to soil nailing designing. The result demonstrates that the increase of shear force can increase optimized nail inclination and makes potential failure surface move towards the back of slope. Also,the shear forces can generate approximately 30% to 50% improvement to factor of safety with the ratio of tensile capacity and shear capacity increasing from 0 to 0.5.