: Mesoporous carbon materials are required for application in various areas. In our previous work, we successfully prepared mesoporous carbon with thin pore walls using inexpensive γ -alumina as a template and sucrose as the carbon source, and proposed a mechanism for the synthetic process. In this work, other carbon source was explored to improve the synthetic process and obtain a better understanding of the synthetic mechanism. Compared with sucrose, phenolic resin generated in situ as the carbon precursor can form a complete and robust carbon layer on the template surface in one polymerization and carbonization procedure, simplifying the synthetic process. In addition, the specific surface areas of the carbon materials were greatly increased when phenolic resin was used as the carbon precursor. According to the proposed synthetic mechanism, the mesopores