Abstract Integrated solar combined-cycle (ISCC) system has better thermal performance than the original gas steam combined-cycle system and a lower initial investment than stand-alone solar thermal plants. However, due to the uncertainty of meteorological conditions, the operation condition of the ISCC system changes continuously. In this study, a dynamic model of the ISCC system is built, and the operation strategies of two ISCC systems with and without the heat storage system are proposed. Accordingly, the dynamic performances of these two ISCC systems on a typical day are compared and analyzed, and the response characteristics of main operation parameters, such as main steam parameters and solar energy power generation, concerning direct normal irradiance (DNI) are obtained. The results show that the stability and security of the ISCC system with a heat storage system are superior to those without the heat storage system during the operation. To verify whether the operation strategy of the ISCC system with heat storage system is universally adaptable under different meteorological conditions, the dynamic performances of the ISCC system are further studied on a good-weather day with a strong DNI and a bad-weather day with weak DNI, respectively.