In this study, the electrical resistance and thermal properties of pitch based carbon fiber(CF) have been studied. To investigate the electrical conductivity of pitch based CF with/without functional groups, nitrogen groups have been doped onto the surface of the CF by urea treatment. Urea treatment has been carried out with different content of urea(1, 3 and 5 g) at 200 °C for 2 h. The resistance and exothermic properties of N-doped CF have been determined a Programmable electrometer and thermo-graphic camera, respectively. The surface morphology and diameter of CF have been also measured by scanning electron microscope(SEM).