This paper introduces a small size and low cost controller of permanent magnet synchronous motor(PMSM). Firstly, the control strategy and the spatial position coordination of PMSM and the controller are described. A small PMSM and the controller are presented by some pictures. Then, the schematic of controller is presented, showing the main control chip, main power chip and the circuit wiring of controller. Besides, position sensors and lead angle are introduced, the influences of the sensors' position and how the lead angle works are discussed. The different control effects are shown by oscilloscope and the motor's working efficiency is tested on dynamometer. At last, by analysing the testing results, we can get some conclusions.