Abstract: A block-on-ring friction tester was used to study the effects of average offline distance on characteristics of pantograph-catenary arc and friction and wear performance of carbon strip. The results indicate that the average offline distance increased with the decrease of normal load and with the increase of sliding speed. The wear rate of carbon strip decreased with the increase of average offline distance when no electric current was delivered. When electric current was delivered, the wear rate of carbon strip and arc energy increased and then decreased with the increase of average offline distance. The wear rate of carbon strip with electric current was much higher than that of carbon strip without electric current. When the average offline distance was very small, main wear mechanisms of carbon strip were oxidative wear, adhesive wear and a small amount of abrasive wear; When the average offline distance was larger, main wear mechanisms of carbon strip were arc erosion and oxidative wear, meanwhile, a small amount of adhesive wear and abrasive wear could be observed.