Drift step recovery diodes (DSRD) are generally used in ultra-wideband pulse signal sources, which can reverse nanosecond-level high-voltage pulse to the load. However, DSRD have high requirements for the rising front edge of the output pulse. A novel wide band gap material step recovery diode with variable doping in the base region was proposed in this paper, in which the doping of the traditional base region would be changed into a stepwise concentration distribution. Built-in electric field was formed by concentration gradient in base region, which would adjust the carrier distribution during the reverse pumping phase of the DSRD discharge circuit and accelerate the carrier extraction. The joint simulation of the device-circuit was performed by Sentaurus TCAD. The results showed that the maximum structure hole velocity at the end of forward injection was increased by 29% compared with the traditional structure, and the voltage rise rate was 19.7 kV/ns, which was 25% higher than the traditional structure (15.8 kV/ns). The proposed structure reduced the time of the reverse pumping stage, and the voltage rise rate of the rising front edge of the output voltage pulse was larger, while the time was shorter. As for the process, only the gas dose of the epitaxial process needed to be changed, which could be realized.