Abstract: Solar simulators simulate the collimation, uniformity, and spectral characteristics of solar irradiation. As the configurations of spacecraft, such as deep space probes, become increasingly complex, the variation in their surface thermal-optical properties becomes more pronounced, therefore highlighting the critical role of solar simulators in thermal balance tests. An introduction to the fundamental composition, operational principles, and performance indices of solar simulators was offered. A comprehensive overview of the current status of solar simulator equipment and performance indices both domestically and internationally was provided. Specific testing requirements for solar simulators were outlined based on the development of spacecraft in China. Typical thermal balance test cases of solar simulators from China and other countries were analyzed. Finally, suggestions and recommendations for the advancement of solar simulators used for thermal balance testing in China were presented.