power subsystem is the support system of spacecraft, which is responsible for the storage, conversion and distribution of spacecraft power. The spacecraft power subsystem includes shunt, charging and discharging, and other protection circuits. The discharge circuit is to ensure the safe and reliable power supply of the battery when the earth shadow period or the instantaneous power of the load is greater than the maximum output power of the solar array. It plays a role in stabilizing the bus voltage and power transmission. The traditional Weinberg discharge regulator circuit has a voltage gain M of 1 M or less than 2, which is only suitable for medium and low voltage bus applications. A high gain Weinberg discharge regulation circuit is proposed for spacecraft high voltage bus power supply. In this paper, the electrical performance and the calculation of the main parameters of the new Weinberg circuit are analyzed in detail. Finally, the 200W experimental prototype is built to verify the experimental results. The experimental results show that the new Weinberg circuit can improve the circuit gain effectively.