The cover-deposition chromium on diamond and graphite single crystal surfaces using X-ray and electron diffraction structure analysis technique have been studied. Under the condition of vacuum of 10-5 to 10-6 torr and the temperature higher than 900℃ while the small grain diamonds or highly oriented graphite platelets hid in electrolytic chromium powder, the Cr3C2 and Cr7C3 can be epitaxially grown on diamond or graphite surfaces. In this paper, we discuss the growth condition of chromium carbide and the physical mechanism of cover-deposition epitaxial growth.