The friction properties of friction pair C/C-40Cr were analyzed and characterized by MMUD-10B friction and wear tester under dry friction and water lubrication conditions with fixed rotation speed of 100 r/min and three different loads（70,150 and 230 N）.The wear marks on the surface of the samples were observed by Olympus GX51 metallographic microscope, the wear amount of each experiment was characterized by J324BC electronic balance, and the morphology of wear debris and atomic ratio of each element were observed by JSM-6510A scanning electron microscope (with EDS energy spectrometer).The experimental results show that in dry friction,the friction coefficient fluctuates at 0.046 to 0.070, and the friction coefficient and wear amount increase with the increase of load, while in water lubrication,the variation range of friction coefficient is small from 0.037 to 0.052, but the wear amount is more.Under dry friction and water lubrication, the friction coefficient and wear amount are positively correlated with the load. Carbon fiber and laminated 40Cr structure exist stably in the wear debris.The wear mechanism is adhesive wear and abrasive wear