A rotor rotation control system for a wind turbine and a control method thereof are provided. The control system includes a rotation unit configured to drive a rotor of the wind turbine to rotate relative to an engine base of the wind turbine, a driving unit configured to drive the rotation unit, and a processor configured to determine a bending moment load switching position on a rotating shaft of the rotor, and output an adjustment instruction to the driving unit based on the bending moment load switching position.