The invention provides a high-efficiency high-power AC/DC power supply circuit capable of eliminating power frequency ripple wave, and a power supply method and a control method therefor. The high-efficiency high-power AC/DC power supply circuit comprises an AC power supply, a rectification filter circuit, a power-frequency ripple-wave eliminating circuit, a DC/DC conversion circuit and a load, wherein the power-frequency ripple-wave eliminating circuit comprises a switching device and an energy buffer circuit; when the voltage of the AC power supply is less than that of the energy buffer circuit, the energy buffer circuit supplies energy to the load; and when the voltage of the AC power supply is higher than that of the energy buffer circuit, the AC power supply supplies energy to the load through the power-frequency ripple-wave eliminating circuit instead of the energy buffer circuit, or the AC power supply supplies energy to the load through the energy buffer circuit and charges the energy buffer circuit. The power supply circuit has a good effect of eliminating the power frequency ripple wave; the extremely low output power frequency ripple wave can be realized by using relatively low capacitance; and in addition, the power device can work under a low-frequency switching state, so that the loss is extremely low and the system efficiency is barely affected.