The conduction charateristics of Na-β(β″)-Al2O3 containing (1-10wt%) fine carbon particles have been investigated. The study shows that the samples containing less than 6 wt% of carbon are still fast ionic conductors and their conductivity is one to two orders of magnitude higher than that of pure Na-β(β″)-Al2O3. The electrical parameters of the samples, such as the bulk resistance, grain boundary resistance, double layer capacitance and leakage current resistance vary with content of carbon. These influences of carbon have been discussed here in some detail. The measurement of conductivity in temperature range from -40℃ to 80℃ shows that Na-β(β″)-Al2O3 containing less than 6 wt% of carbon are good materials for making double layer capacitor.