Different modal admittance matrix, obtained according to different harmonic model of non-linear loads (NLLs), may have a big influence on the modal impedance and modal frequency in a resonance mode. The effect of load modeling of high-speed train on resonance behavior of high-speed railway traction supply system employing modal sensitivity of modal analysis approach is investigated. Results inferred from the driving point impedance curve got from frequency scan are compared with those of the modal sensitivity analysis with three different NLL models. The results show that different NLL models produce closed resonance frequency zone in the same resonance modes.