HXD2 and SS4B were selected as the representative of AC drive and DC drive electric locomotive respectively. Based on theactual measured data, their electrical load performance were compared in four aspects, i.e. working principle, power factor, harmonic currentand the locomotive consumption. The technical advantages of AC drive electric locomotive were illustrated. With the production halts of DCdrive electric locomotive and more and more AC drive electric locomotive putting into service, the properties of high power factor, lowharmonic current and regenerative braking ability should be fully considered when designing the traction power supply system of electricrailway. Meanwhile, it was also necessary to know the harmonic characteristics of AC drive electric locomotive in detail so as to provide thebasic data for the designing of traction power supply system.