The invention discloses a torque calculation optimization method based on direct torque control and predictive control. A voltage vector selection region is determined by a stator magnetic flux linkage comparator and a torque comparator; the region is quartered; a stator magnetic flux linkage amplitude and a torque value are input into an objective function to select a minimum value; an interval and an angle of a voltage vector are selected; the voltage vector is selected in an interval given by an interval table and the voltage vector after synthesis is output; the stator magnetic flux linkage amplitude is obtained according to a stator magnetic flux linkage variation diagram; a torque formula is determined by the stator magnetic flux linkage amplitude; the torque formula is subjected tooptimization processing; and by a relative error of a conventional torque formula and the optimized torque formula, feasibility of the optimized torque formula is verified. According to the invention,the optimized torque formula can replace the conventional torque formula so as to improve performance of a permanent magnet synchronous motor direct torque control system and reduce torque pulsation;and switching frequency is stable.