The curing reaction kinetics of polyethylene glycol(PEG) with isophorone diisocyanate(IPDI) or toluene diisocyanate(TDI) were studied by means of chemical titraction. The reaction rate constant and activation energy (E_a) were obtained. The effect of the molecular weight of PEG ,activation of curing agent, temperature and combustion catalysts on curing reaction were discussed. The results show that the reaction order are second. The E_a of PEG/IPDI and PEG/TDI system are 46.89 kJ·mol_-1 and 41.12 kJ·mol_-1, respectively. With the increase of temperature and activation of curing agent, the reaction rate constants increase. The activation of cure agent and combustion catalysts have no effect on the order of reaction, but affect the reaction rate constants.