Abstract: A two-phase flow simulation model for steam condenser was established, according to the structure and work characteristics of high pressure and specified pressure of the steam condenser. By means of the model, steady-state calculation and dynamic characteristic simulation of the steam condenser were performed. The steady-state simulation results were verified with the steam condenser test results. The results show that the developed model can be used to simulate the steam condenser of the marine nuclear power plant dynamics in real-time. The research results can be meaningful to the design of the operation and control system for secondary system start-up and shut-down.