Abstract: The character and kinetics of curing reaction were studied by means of FT-IR and differential scanning calorimetry (DSC) for cyanate ester resin modified thermosetting butadienestyrene resin. The extrapolating temperatureheating rate method was used to determine the initial temperature (Ti0), peak temperature (Tp0) and terminal temperature (Tf0) of the resin, which are 414.2,444.5 and 460.6 K， respectively, in order to optimize the curing process of the modified resin. The reaction order and the apparent activation energy with different scanning rates were estimated according to FreemanCarroll’s method. Result shows that while the scanning rate is less than 5 K/min, the reaction order and the apparent activation energy are 1.2 and 155.1 kJ/mol， respectively. While the scanning rate is equal to or greater than 5 K/min, reaction order and apparent activation energy are 2 and 188.7 kJ/mol, respectively.