The invention discloses a fault position identification method during DC harmonic protection action. The method is characterized in that harmonic components of a direct current at a rectification side and an inversion side are detected simultaneously; and actual position of the fault is judged according to relative magnitude of the harmonic components of the direct current at the two sides, and further measures are taken as needed. The fault position identification method is especially suitable for DC power transmission projects where a DC line has an amplification effect on the harmonic wave; the position of the fault can be indicated accurately during DC harmonic protection action; and meanwhile, corresponding measures for preventing misoperation and refusal-operation of the DC harmonic protection can be taken according to practical situation.