Porous carbon materials with high specific surface area and wide pore size distribution play a crucial role in the energy storage process. In this paper, a mixed sol-gel system of carbon source, chemical activator and salt template agent was constructed using raw pitch, o-xylene soluble substance and their mesophase as carbon source, NaCl as template agent and KOH as activator. After one step process of high temperature treatment, porous carbon materials with high specific surface area (SBET 1969 m2/g) and wide nanopore distribution (0.4–6 nm) were obtained. The electrochemical properties of the prepared mesophase porous carbon materials were tested. At a charge-discharge rate of 80 mA/g, a specific capacitance of 102.5 F/g can be achieved for porous carbon materials obtained from the o-xylene soluble mesophase, indicating the feasibility of preparing porous carbon electrode materials by o-xylene soluble mesophase. The development of template/activation synchronous pore-forming technology can integrate the advantages of the two kinds of pore-forming technologies, reduce the demand for pore size control in porous carbon materials, and promote the one-step realization of porous carbon materials with high specific surface area, wide pore size distribution and controllable pore size.