The invention relates to a three-phase PFC rectifying device of a high-power charging pile with a boost-buck function for electric cars and a control method. The device comprises a rectifying module,a boost-buck module, a sampling module, a hardware voltage and current detection module, a comparator module, a DSP module and a protective switch tube driving module, wherein three-phase network voltage is connected with the rectifying module through pin output ends UA, UB and UC, and the rectifying module and the boost-buck module form a three-phase eight-switch buck-boost rectifier. In the three-phase PFC rectifying device, the three-phase eight-switch buck-boost rectifier is used as a main circuit topology, and double closed loop control is adopted, so that the input current is close to asine wave, the input current and the input voltage are cophasal, and the power factor approximates to 1; the structure is simple, the size is small, the grid-side power factor is high, and the charging efficiency is high; besides, the direct-current side is connected with the buck-boost topology, the output voltage can be flexibly adjusted according to the type of an electric car at the output end, different requirements for the output voltage are met, and the electric cars of different types can be quickly charged.