Vector control technology is regarded as a kind of controlling manner of AC asynchronous motor and it has already become the first method of the high-performance variable-frequency speed regulating system. According to the basic principles of induction motor vector control, this paper constructs simulation model of rotor magnetic field oriented vector control system based on the MATLAB software. The paper analyzes the operation of motor on the basis of mutation of a given speed and sudden load. The simulation result including the oscillogram speed, torque,three phase current and two phase current were presented and analyzed. Results show that it has good dynamic performance, and it realizes the decoupling control system.