Background: System code is important for the dynamic simulation and safety analysis of the molten salt cooling system. There is no professional system code for molten salt-cooled system yet. The HYSYS code is a process simulation environment designed to serve many processing industries. It has a potential ability for the global simulation of the molten salt cooling system as well as transient and accident safety analysis. Purpose: The aim is to validate the modified HYSYS code for molten salt cooling system application. Methods: Based on the KNO_3-NaNO_2-NaNO_3 molten salt (HTS) experiment device, the thermal-dynamic and transport properties were implemented into the HYSYS code, and a precise and complete model was built for HYSYS code. The model was used to simulate the HTS loop under different conditions. The corresponding experiments were also executed, and then the simulated results were compared with the experimental data to validate the HYSYS code application. Results: The simulated temperature data are in good agreement with the experimental results. Conclusion: The modified HYSYS code is available in simulating molten salt-cooled loop system.