The invention provides an electric spark processing power supply and a control method thereof. The electric spark processing power supply can comprise a microcontroller, a driving circuit, a first power circuit, a second power circuit and an electrode; the microcontroller generates a trigger pulse signal and a current setting signal on the basis of an electrical processing command; the driving circuit generates a first pulse signal on the basis of the current setting signal and generates a second pulse signal and a third pulse signal on the basis of the trigger pulse signal; the first power circuit generates a first voltage signal under the control of the first pulse signal; the second power circuit generates a second voltage signal under the control of the third pulse signal; the electrode is coupled to the first power circuit and the second power circuit so as to receive the first voltage signal and/or the second voltage signal, wherein the first power circuit comprises first by-passconnected with the electrode in parallel, the first by-pass is selectively turned on or turned off under the control of the second pulse signal so as to control the first voltage signal to be provided for the first by-pass or the electrode.