A DC supply slugging circuit includes a transistor switch and a switch control circuit connected between the grating and the drain of the switch and connected with the input supply, said switch control circuit adjusts the character of the junction capacitance between the grating and the drain of the switch to be expressed as linearity so that the voltage of the source and drain changes in linearity, which can realize that the output slugging voltage changes in fixed tilted ratio and the change is controlled and the instant striking current can be controlled accurately.