Thermal plasmas are promising as a new heat source to produce special grades of carbon black with high crystalline structure of graphite and sheet-like morphology. In this paper, carbon black was formed by direct decomposition of methane using DC (Direct Current) plasma torch with rod-nozzle type electrodes at different methane flow rates of 5 and 7.5 slpm, and then, characterized to find the variation of its characteristics under the different thermal plasma environment. From the results, it is found that more parts of carbon black have a special morphology of wrinkled sheet with the high degree of graphitization at the methane flow rate of 5 slpm in comparison of carbon black samples at 7.5 slpm. Considering the temperature drop when the methane gas is injected into the periphery of a DC arc jet, these results indicate that the formation mechanism of special grade carbon black with high graphitization and sheet-like morphology is significantly dependent on the temperature gradient around arc jet periphery as well as methane decomposition temperature itself by thermal plasma.