Power factor correction（PFC）circuit are usually used to solve the harmonic pollution matter of power electronics. In highpower special applications, Threephase Boosttype power factor correction has a disadvantage of its high and narrow output voltage and not good for design of DC/DC. The paper studies on a more efficient threephase Bucktype PFC based on Swiss topology, analyses its operational principle and control strategy. Simulation verification by MATLAB/Simulink platform is carried on. A 10 kW experimental prototype using DSP for control is designed and developed, and experiments are carried on. Experimental results show that the circuit can achieve a stable 400 V voltage output, power factor approaches 1, efficiency over 97% at full load. It proves the feasibility and superiority of the circuit.