Cure kinetics of DGEBA(diglycidyl ether or bisphenol A)/MDA(4.4'-methylene dianiline) system with NPG(neopentyl glycol) as a reactive additive was studied by differential scanning calorimetry(DSC). The activation energy and pre-exponential factor were calculated by Kissinger equation from the data of dynamic DSC thermograms. The values of activation energy and pre-exponential factor decreased with the increment of NPG contents. With the increment of NPG content cure rate constant increased, and this meant that tile hydroxyl groups of NPG acted as a catalyst.