The invention discloses a control method of a high-accuracy adjustable servo motor. The control method comprises the steps of 1, dividing a plurality of rotational speed zones and temperature zones; 2, recording a curve graph of a current deviation value, changing with a rotor position, of the servo motor under each rotational speed zone and each temperature zone; 3, performing parameter self-setting of the servo motor; 4, providing a rechargeable battery pack, and arranging a capacitor between a positive electrode and a negative electrode at an output end of the battery pack; 5, respectivelyarranging three inversion circuits at two ends of the capacitor, wherein the difference among voltage phase sequences of output second ends of the three inversion circuits is 120 degrees; and 6, connecting a power input end of the servo motor to a three-phase AC power supply, acquiring a phase voltage and a phase current of three phase inputs of the servo motor in real time, and switching the output second ends of the three inversion circuits as an input power supply of the servo motor when the phase voltage of an arbitrary phase input exceeds a set voltage range. By the control method, the technical problem that the control accuracy of the servo motor cannot be further improved is solved.