The invention belongs to the technical field of power grid harmonic detection, and relates to a method for inhibiting current harmonics based on FFT (Fast Fourier Transform). According to the technical scheme of the invention, the method can extract any harmonic and the sum of harmonic components meeting conditions. When a load harmonic current exceeds the compensation capacity of an APF, the method can select the characteristic harmonics with the bigger dangers to be compensated. The method can carry out IFFT of the harmonics meeting the conditions, and then extracts the sum of a part of harmonic components, so that the APF just compensates the needed harmonics in an occasion where the method is used cooperatively with a passive filter.