DSA200 pantograph and CH160 catenary are being in service in China on SS7 electric locomotive. Dynamic study of the pantograph/catenary system found that the contact force between pantograph and contact wire vibrated periodically with the running of trains. Both of the amplitude and frequency of the dynamic contact force increased with the increase of running speeds. In this paper, the effects of dynamic contact force on tribological properties of the pure carbon strip were studied on a homemade pin-on-disk tribometer. A critical point of friction coefficient, wear rate and current-carrying quality at the velocity of 80 km/h was detected subjected to dynamic contact force. Tribological properties of the pure carbon strip deteriorated abruptly when the train ran faster than 80 km/h. Oxidation film on the surface of the strip was produced firstly, and then it grew slowly, at last it was destroyed rapidly with the increase of the running speeds. This transformation leaded to the sudden shift of friction coefficient and wear rate. Meanwhile, the critical point of arcing rate (2%) at 80 km/h was tested. Current-carrying quality of the strip deteriorated abruptly accompanied by the rapidly raised arcing rate. Simultaneously, cracks were generated and extended inner the strip. These cracks destroyed the strip's mechanical property and accelerated the arc erosion. The wear mechanism transferred from mechanical wear to arc erosion with the increase of arcing rate, which were proved to be the most important failure types for pure carbon strip. This study obtained the evolution processes of the tribological properties in pantograph/catenary system, expecting to provide some useful suggestions for the safe operation of locomotives.