Abstract: Taking into account the errors of discharge pressure between experimental and computational values are off limits by the empirical models,one-dimensional theory model of steam-water two-phase lifting pressure facility is constructed and solved by the results based on direct contact condensation,and some key issues,such as inter-phase mass transfer and phase volume fraction,are discussed in detail.In order to vali-date the model,the maximum discharge pressures are computed and the results are relatively precise to the corresponding experimental data.The maximum discharge pressures at various inlet parameters are also con-cerned,and the results show the maximum discharge pressure is descended by improving the water tempera-ture,but improved by improving the inlet water mass flow or steam pressure.