Abstract: In order to develop a simulator for the pebble-bed modular high temperature gas-cooled reactor HTR-10, a real-time thermal hydraulic model of the steam generator was established on the integrated simulation support platform vPower. The model was based on the heat transfer equation to solve the temperature and enthalpy of primary and secondary fluid and the temperature of heat transfer tube, and the flow network tools were used to calculate the pressure and flow rate on both sides. Three kinds of node division schemes were discussed, and recommendations for the application scope of different node division schemes were given. The 96 node division scheme was used for follow-up research. In addition, the accuracy and rationality of the main parameters and distribution parameters of the model under steady-state conditions were confir-ed through analysis. On the basis of 100% power steady-state condition, the helium flow step conditions were simulated, and the changes of the main parameters in the model were analyzed. The dynamic simulation results show that the helium flow step will cause the primary and secondary side parameters to change in different degrees, the change amplitude is proportional to the step degree, and due to the heat capacity of the metal pipe and the water/steam, the change rate of the secondary side parameters is slower than that of the primary side; the rebalancing time of the model is short which indicates that the thermal inertia of the helical tube steam generator used in HTR-10 is relatively small.