The space radiator is responsible for dissipating the redundant heat from spacecraft to outside space. It is a key equipment of the thermal control system for spacecraft，especially for manned spacecraft. The currently launched manned spacecrafts all use fluid loop radiators，which should meet the requirements of long lifetime，high reliability，and stability. In this paper，the fluid loop-heat pipe coupled radiator for the China Space Station (CSS) is tested and analyzed，and the expression of the heat rejection capacity of the radiator is concluded. First，the scheme and process of the tests are briefly introduced，and the test results are given. Then，through the analysis of the obtained test data，the relationships between the heat transfer resistance and the heat rejection capacity with the fluid loop parameters and the external heat flux parameters are obtained. Based on the test data，the simulation analysis model of the radiator is improved. The results obtained by the improved model are compared with the test data，and good agreement is achieved. The simulation analysis model can be used to predict and analyze the on-orbit performance of the radiator. This article has certain reference for the design of spacecraft radiator，and can provide data support for spacecraft thermal balance tests and radiator working state settings in orbit.