Operation and control of a high speed cryogenic flow is an indispensable technique in the aerospace technology as represented by examples of turbopumps for rocket engines. The liquid-gas mixed phase, in which vapor bubbles are created by cavitation, must be taken into account in cryogenic fluids. Though homogeneous models or two-fluid models had been used in flow analyses with cavitation, they had difficulties in reproducing bubble distributions and in treatment of the creation and annihilation of bubbles. A new model, which could predict cavitation in the flow in a complex structure, was constructed and the numerical code based on this model was developed. A simulation study of a cavitating nozzle flow in a sub-cooled liquid nitrogen was carried out using this code. The simulation results were compared with NASA experimental results of the sub-cooled liquid nitrogen nozzle flows with cavitation under the same test conditions. The simulation results such as the pressure distribution on the nozzle surface were in good agreement with the experimental results.