This research looked at the thermolability of the MCM-48-NaCl catalyst in the esterification of nyamplung oil. The use of various calcination temperatures was to investigate the thermolabile catalyst's optimization. The activity of the catalyst in the esterification was determined using the acid-base titration method. The active site and thermolabile state of the catalyzed were determined using XRD and FTIR characterization. In the esterification, the CTAB-MCM-48-NaCl catalyst performed 12.36% better than the conventional catalyst (H2SO4). The catalyzed achieved its optimum condition at calcination of 650 °C, with a reaction activity of 21.44%. Bronsted acid and surfactants are active sites of catalysts that play a role in the reaction. The presence of NaCl did not significantly affect the thermolabile resistance of the MCM-48-NaCl catalyst. This catalyst has the potential for esterification and hydrocracking hydrocarbon compounds of nyamplung oil suitable for biodiesel.