In order to investigate the interaction between the worn surface morphology of friction pair and arc in the process of currentcarrying friction and wear,the tests were carried out on the HST100 high speed currentcarrying friction and wear tester using Cu/QCr 05 as friction pairs.The worn surface roughness was measured by a 3D profilometer and the surface morphologiesy of the pin samples were analyzed by scanning electron microscopy.The results show that the initial surface roughness has an influence the arc energy and friction coefficient at primary stage of wear,but it has not significant influence in the mid and late stage of wear.The change of surface roughness is related to the arc rate and arc energy,large surface roughness will result in large arc rate and arc energy,and arc rate and arc energy will decrease along with the decrease of surface roughness.In the process of friction and wear,the change of wear rate presents ‘U’ shape while friction coefficient experiences the process of descending first and then ascending.The arc erosion is not obvious at primary stage of wear and the wear mechanism is mainly adhesion wear,but in the mid and late stage of wear,arc erosion is increasingly serious,resulting in arc ablation craters and fused deposition.