Due to the increasing speed of the locomotive, the pantograph-catenary disconnection was getting worse, and the pantograph arc occured frequently. The pantograph arc etched the pantograph slider and contact wire, and the etching level was influenced by arcing energy. In this paper, the arc voltage and current of different traction current and power factor was measured by pantograph-catenary arcing test system. The relationship between average arcing duration and traction current, power factor of load was analyzed, as well as the arc energy affected by power factor of load was studied. The results showed that the average arcing duration becomes longer in index with traction current increasing; the arcing duration with inductive load is longer than with resistive load; the arc energy decreases with the rising of load power factor.