With the development of power electronics，the technology of Switching Mode Power Supply(SMPS) is gradually perfected. However，there is no end to the demand for a high power and high performance power supply. Nowadays, Power Factor Correction (PFC) technique is widely researched. This paper mainly analyzes the fundamental configuration of the switching power supply. And we study the basic structure and the operating principles of ZVT-boost soft-switching PFC circuit and the implementing principle of soft switch. For the power requirements, the two-stage PFC circuit is used. The forward stage is a single-phase Boost Power Factor Correction circuit and the backward stage main circuit is a full-bridge converter with the phase-shifting control soft-switching technique. Finally the simulating analysis is performed to the designed system.