Based on the analysis of the automatic cab lifting devices, a permanent magnet motor was designed to drive the piston pump. With the analysis of three classes of permanent-magnet materials for electric motors, the NdFeB permanent-magnet materials was selected to output enough power for the motor. The dimensions of the magnet and the rotor were determined through theoretical calculation and analysis. NdFeB permanent magnet pump motor has some characteristic as follows: low failure rate, simple structure, high reliability, low noise, high power. It can improve the safety, comfort and manipulation convenience of heavy truck.