Abstract: In view of problem of severe distortion of local current wave caused by increase of low-voltage single-phase electrical equipment, a kind of single-phase harmonic suppression system used in low-voltage system was designed. The system uses instantaneous current detection control method to detect current harmonic content, so that the converter generates a current component which has the same amplitude and opposite phase with current harmonic, and can fully offset system current harmonics. Experimental results show that the system has good effect of compensation, and makes harmonic distortion rate fall from 76.3% to 10.4%.