In order to study the influence of the viscosity of the lubricant on the quality of the precision cutting section,the shear processing experiment was carried out with the non oriented electrical silicon steel of 05 mm thick under different lubricating viscosity conditions.The shear section morphology,the working hardening and the shear force of the electrical silicon steel shearing were compared.Through comparison experiments,it is found that the improvement of lubrication conditions in the precision shearing process of electric silicon steel,the quality of the shear section of silicon steel is improved,the height of the shear zone is increased,the height of the rollover and the height of the burr are reduced,and the work hardening is reduced.When the viscosity of the lubricant is small,the shear force is decreased obviously,and the tissue flow area of the corresponding shear region is significantly decreased,and the shear zone height is significantly increased.The results show that the difference in lubricant viscosity directly affects the lubrication state between the tool and the sheet during the shearing process of the sheet,which affects the shear force and the material deformation state,and further affects the shear section microstructure flow and shear quality.