The kinetics of the cure reaction for system of o-cresol formaldehyde epoxy resin (o-CFER)/succinic anhydride (SA) and tertiary amine as a catalyst was investigated with a differential scanning calorimeter (DSC). Autocatalytic behavior was shown in the first stages of the cure for the system, which was well described by the model proposed by Kamal(6) that includes two rate constants, k(1) and k(2), and two reaction orders, m and n. The overall reaction order, m + n, is in the range 2.1 similar to 2.6, and the activation energy for k(1) and k(2) was 109 and 72.0 kJ/mol, respectively. In the later stages, a cross-linked network was formed and the cure reaction is mainly controlled by diffusion. Diffusion factor, f(alpha), was introduced into Kamal's equation, then the calculated values agree very well with the experimental data. The molecular mechanism of this curing reaction was discussed.