Abstract: A novel harmonic current detection method for three\|phase three\|wire shunt active power filter is proposed in this paper based on the analysis on nonlinear current introduced by rectifier bridge. Then the principle of the harmonic current detection method and its implementation are illustrated, and the design method of harmonic current detection filter is also discussed. The influence of the harmonic detection method on dc bus voltage is analyzed and studied in case of abrupt load change, and the cause of dc bus voltage fluctuation is also given. In the end, harmonic current detection method and the proposed method are studied separately through experiment and simulation, which verify the feasibility and reliability of the novel harmonic current detection method.