The configurations of a three-phase buck-boost power factor correction (PFC) circuit are provided. The circuit includes a first single-phase buck-boost PFC circuit receiving a first phase voltage and having a first and a second output terminals and a neutral-point for outputting a first and a second output voltages, a second single-phase buck-boost PFC circuit receiving a third phase voltage and coupled to the first and the second output terminals and the neutral-point, a first to a fourth thyristors, each of which has an anode and a cathode. The anodes of the first and the third thyristors and the cathodes of the second and the fourth thyristors receive a second phase voltage, and the cathode of the first thyristor and the anode of the second thyristor are coupled to the first single-phase buck-boost PFC circuit.