The invention discloses a harmonic responsibility distinguishing method considering background harmonic voltage, comprising the following steps: (1) collecting voltage and current signals at a point of common coupling PCC of a distribution network and a current signal at the head end of a user feeder; (2) acquiring the harmonic components of the collected signals; (3) calculating the lumped power and lumped active power of each harmonic at the point of common coupling PCC of the distribution network; (4) screening and separating the harmonics at the point of common coupling PCC of the distribution network; (5) acquiring the lumped equivalent conductance and harmonic equivalent conductance at the point of common coupling PCC of the distribution network; (6) calculating the three-phase current of background harmonic; (7) calculating the lumped power and lumped active power of each harmonic at the head end of the user feeder; (8) screening and separating the harmonics at the head end of the user feeder; (9) calculating the three-phase harmonic current of the feeder at an Mth user side; and (10) distinguishing the harmonic responsibility. The harmonic responsibility can be precisely located to each user, the content and component of each user's harmonic can be accurately calculated, and fair punishment can be carried out.