The requirements of the power supply design are proposed based on the principle of discharge process in depositing & welding power supply, and a depositing & welding power system schematic is designed according to the requirements. The control manner of the power supply combines RLC (Resistance-Inductance-Capacitance) circuit with fast SCR, and the deposition and restoration can be achieved by using the NE555 circuit to trigger the fast silicon controlled rectifier. Furthermore, parameters such as voltage, capacitance, frequency, motion mode of electrode are probed into, a depositing & welding test is experimented and the waveform of the power supply are analyzed. According to the results of experiments and analysis, it is clear that the output of the power supply can meet the requirements of working successfully and achieve the required standard to do electrospark depositing and welding operations. However, the actual working electrospark frequency is lower than the trigger pulse frequency added on the fast SCR, which result in a lower efficiency in depositing & welding work. Main reasons for this situation is that the relative movement of the electrode and the work-piece can’ t guarantee the best conditions for electrospark and the fast SCR in circuit can’t be reliably turn-off fast. These research laid foundations for further electrospark depositing & welding power supply design and efficiency improvement.