An epoxy/anhydride system was modified by aromatic diamine-based benzoxazine. The curing mechanism of the system was analyzed with Fourier transform infrared spectroscopy(FT-IR)and differential scanning calorimetry (DSC). The blend system exhibited two curing reactions in the curing process. Epoxy resin first cured with sufficient anhydride catalyzed by imidazole at 100℃

and cured completely at 150℃ for 2 h. Benzoxazine underwent ring-opening polymerization at 180℃. The curing kinetics of modified resin system was studied with non-isothermal DSC at different heating rates. The average activation energies of two reactions were calculated utilizing the Flynn-Wall-Ozawa method to be 65.27 kJ·mol-1 and 92.8 kJ·mol-1

respectively. Both curing reactions were found to be autocatalytic processes by the Friedman method

and the predicted curves from the autocatalytic model fitted well with those of experiments.