The invention discloses a high-power synchronous rectification high-frequency switching power supply. The high-power synchronous rectification high-frequency switching power supply comprises a case, afirst conductive busbar, a second conductive busbar, transformers, a main control circuit, a three-phase input rectifier stack, a rectifier bridge module circuit board, a chopping module and a secondrectifier module. The first conductive busbar is positioned at the upper portion of the second conductive busbar, the first conductive busbar and the second conductive busbar are inserted in the casein parallel and in a staggered manner, one end of a conductive double-hole busbar is connected with the main control circuit, the other end of the conductive double-hole busbar extends out of the case, the transformers are fixedly arranged at the lower portion of the first conductive busbar in the extension direction of the first conductive busbar, the second rectifier module is arranged on the first conductive busbar and the transformers, and the chopping module, the three-phase input rectifier stack and the rectifier bridge module circuit board are arranged on the second conductive busbar.The switch power supply provided by the invention has the advantages of simple and reasonable arrangement of all parts, a compact structure, convenience in installation, disassembly and maintenance and good heat dissipation effect.