Abstract: This paper aims to propose a two-phase critical flow model to accurately evaluate the leakage rate of pipeline breaks. The critical flow model considering the nucleation of metastable liquids and non-equilibrium mass transfer is based on a two-fluid model coupled with an isothermal bubble growth model. The model is implemented by an explicit difference algorithm. The proposed model calculates fast and the model predictions exhibit strong similarities with the experimental data. The numerical research of the leakage process for critical flow is conducted. The results show that the subcooling has a significant effect on the fluid flow and the mass transfer process, while the upstream pressure only affects the fluid flow. The proposed model can provide a theoretical basis for the safety analysis of pressurized pipelines and vessels.