Abstract: When grinding the main roller of a lithium battery coating machine, the grinding force has a significant impact on the deflection of the main roller surface. In order to study the influence of the main roller structure, grinding depth and grinding position on the deflection of the main roller, the theoretical formula was used to calculate the grinding force applied to the main roller during grinding by a grinder. Then, the ANSYS finite element simulation software was used to perform static simulation on two types of main rollers, namely, shaft-through type and hollow type, to compare the deflection changes of the two types of main rollers. Finally, the influence of different grinding depths and different grinding positions on the deflection of the hollow type main roller was emphatically studied. When the grinding depth is constant, the deflection of the left roller surface in Z direction of the main roller approximately satisfies a quadratic curve relationship when grinding at different positions of the main roller. The research results have certain guiding significance for the structural design and grinding process of the main roller.