Waveform correlation method with time-domain waveform cannot estimate the responsibility of every harmonic current. When the emission level of harmonic current is low, Waveform correlation method is insensitive to identify harmonic sources. In order to solve the problem above, a phase-free harmonic source identification method combined with waveform correlation is proposed. The method is based on correlation coefficient combined with the harmonic coefficient. Current and voltage amplitudes are the only information needed for this mathematical model rather than the time-domain waveform, or harmonic phase. This method can not only reflect the nonlinear degree of load sensitively, but also quantitatively express the relationship between the nonlinear degree of load and harmonic current. To a certain extent, the harmonic responsibility of every harmonic component can be assessed by using this method. The validated of the proposed method is verified through simulation study and field test.