The alternating current dynamo with invariable speed is used in many pumping stations at present, which wastes lots of electric energy, but the common speed regulation is relatively difficult due to the high-voltage. In order to solve the problem above,we provided a doubly-fed speed regulation system. An AC/AC cycloconverter was taken as main circuit, and the vector control of stator magnetic field orientation was adopted in this system. Besides,we provided the block diagram and flow chart of main program for control part of the system, and simulated the overall system by MatLab/Simulink, and obtained the simulation waveform. The simulation results indicate that the speed regulation system has small harmonic stator current, high control precision, quick dynamic response and stable working performance. In addition, the capability of frequency converter can be decreased largely and the costs are reduced dramatically with limited speed range, so the system has broad application prospect in the speed regulation of pumping station motor.