Starting from the design principle of quasi-continuous fiber laser power supply, this article analyzes the power demand of quasi-continuous fiber lasers. According to energy conservation, by controlling the change of energy storage capacitor energy, a laser diode power supply driving solution is proposed and analyzed. First Boost boosted and Buck constant current secondary circuit topology, developed a high power density, high efficiency, low ripple quasi-continuous fiber laser power supply system, through experiments and batch production verification of the whole machine shows that the power supply The system satisfies the stability and reliability of instantaneous high-current output, and realizes the precise and controllable output laser energy, which has practical reference and reference significance for the subsequent development and application of high-power QCW lasers.