The invention relates to a torque control method and device of a permanent magnet synchronous motor. The torque control method of the permanent magnet synchronous motor comprises the following steps:looking up an I data table to obtain a quadrature-axis current given value I under the current torque when the motor speed reaches above the base speed, wherein the I data table is a datatable generated by the quadrature-axis current given values under different torques and speeds measured through a bench test; obtaining a voltage feedback vale U according to a direct-axis voltageU and the quadrature-axis voltage U, and obtaining a direct-axis current given value I through the regulation of a regulator after making difference between a direct current voltage given value U and the voltage feedback vale U; and controlling the output torque of the motor according to the quadrature-axis current given value I and the direct-axis current given value I. According to the invention, a current quadrature-axis current instruction I is given through magnetic weakening control by means of the I current look-up table method when above thebase speed, therefore, not only the amount of the data obtained by looking up the table is reduced, but also the link of correcting the torque error is reduced; thus, the problems of high vibration and slow response of the permanent magnet synchronous motor in high speed operation are solved.