Abstract: To reduce the size of the control system of a high-speed brushless direct-current motor without affecting the realization of the system functions, its control power and drive power used the same power supply. However, experiments showed that such a design of using the same power had a defect of signal crosstalk. A design of discrete power control system was proposed in this paper. Firstly, the drive power and control power were designed separately, then the signal processing system, signal distribution system and power protection system were improved. The comparison test of the power control system before and after improvement was carried out, and the results show that after adopting the discrete power control system, the control power supply can be fine controlled at 0-12 V, and the driving power supply can be wide output at 0-100 V. After the improvement, there is no crosstalk between the control power supply and the drive power supply, that is, the control circuit will not overload and the drive circuit will not underload. The above results show that the discrete design of the motor driving power and the control power realizes the fine regulation of the control signal and improves the accuracy of the electric signal detection in the operation process.