Abstract: By using MMS-1G pin-on-disk high temperature and high speed friction and wear tester, the tribological properties of CrNiMo steel-H96 copper couples in nitrogen atmosphere were investigated. The morphologies of worn surface of pin specimen and the main element of debris were studied by using JSM-5610LV SEM and EDAX. The results indicate that the friction coefficient decreased and the wear rates increased as pv value increasing in nitrogen atmosphere. Wear mechanism changed from adhesive wear to adhesive wear and abrasive wear with pv value increasing.