In order to measure the solar heat gain coefficient of shading window system accurately, a test platform for determination of the solar heat gain coefficient was set up. Firstly, the construction of the platform was introduced, the platform is mainly composed of solar simulator, environment rooms, hot box, specimen, heat metering box, circulating water temperature control and measurement system, etc. The measurement of the net heat flow between two incubator boxes is based on the principle of steady heat transfer. Thermal physical parameters, such as temperature, flow rate, the intensity of solar radiation can be monitored by the platform real-timely, so these parameters can be automatically detected, monitored and stored, so as to realize the intelligent control. Secondly, three vital calibration tests and test method were discussed in detail. Finally, typical specimens were tested, and the test results were compared with the calculated value of Windows 7.4, results show that the test data and calculated data has good consistency, and the test platform has high reliability. © 2019, Editorial Board of Acta Energiae Solaris Sinica. All right reserved.