The two-phase model(TPM) is proved to be available in calculation of jet singlet oxygen generator(JSOG). The result of numerical simulation illustrates that the type of the generator kinetics is dependant on the relative concentration between chlorine and BHP, when the other parameters are fixed. An improved method determining the type of the generator kinetics by using the curve of chlorine absorption rate is presented. The TPM, including the thermal effect, could compute temperature and the fraction of water vapor. The results agrees with the experiment well.