In order to study how to accelerate the response of permanent magnet synchronous motor to torquevariation，a direct torque control system of permanent magnet synchronous motor based on TC1782 is introduced inthis paper. The control center of the system is infineon TC1782. It uses ADC chip named AD7606 to acquire themotor phase current simultaneously，and uses resolver chip named AD2S1210 and resolver to obtain the positionand angle of the signal rotor. LABCAＲ motor simulation device，as a hardware simulation platform，combined withthe control portion，constitutes a closed loop control system. Through the experiment，we know this design isstable. Because of incorporating the feedback linearization module， the system has fast dynamic responsecharacteristics and smaller torque ripple. Speed and torque can follow the system. This design can meet therequirements of controlling permanent magnet synchronous motor.