To eliminate the zero-sequence harmonic currents in the neutral lines caused by unbalanced and nonlinear loads in the three-phase four-wire distribution power system， a novel zero-sequence harmonic current mitigation approach is proposed by integrating zig-zag transformer and zero-sequence damper together. The simulation and laboratory experiments under different operation conditions indicate that the proposed method can effectively eliminate the zero-sequence harmonic currents. It has simple configuration， and is not influenced by the system parameters. It can effectively filter out harmonics， and significantly improve the power quality and reliability.