Ceramics/carbon composites have been used widely, Such as, the magnesia/carbon refractory was used in some DC electric arc furnaces as anode, because of its high temperature performance and electrical conduction. The ceramic/carbon composite was easily oxidized in high-temperature at atmosphere with oxide, so the test of high-temperature electrically conducting properties needs protection. This paper proposed a test method and equipment for specific resistance both in room and high temperature, according to the electrically conducting property of ceramics/carbon composite. And the specific resistance of magnesia/carbon composites (C content <20%) was tested by this equipment. It is showed that, as the carbon content growing, there is a threshold at which the specific resistance falls sharply. Moreover, as the heating temperature increasing, the composites’ specific resistance shows a “gradual- sudden- slow- comparatively steady” changing process. The minimal specific resistance level of the developed ceramics/carbon composite (C content<20%) is about 10-5Ω·m.