The principles of pitch bearing soft belt and deformation calculation were described. Taking a large wind turbine rotor bearing as the research object, the finite element method was used to apply the limit load and fatigue load on the pitch bearing at different angles, and the maximum relative displacements of pitch bearing inner and outer rings at different angles were calculated. Based on the displacement, the design position and the grinding amount at the position of the bearing soft belt in the subsequent processing were determined, so the bearing damage caused by the load on the soft belt position during the operation of the wind turbine was avoided.