Abstract: With the increasing demand for data capacity of deep space laser communication systems,the wavelength division multiplexing(WDM) technology will become an effective method to expand communication capacity. It is necessary to study the performance variation of EDFA WDM characteristics under deep space radiation conditions. The effects of deep space radiation and temperature field on the performance of EDFA,non-uniform characteristics are analyzed,and the gain influence model between EDFA WDM signals under deep space radiation conditions are established,and the evaluation method of the influence of nonuniform variation of gain is given. Deep space radiation environment was simulated, and the electron irradiation and neutron irradiation were used as radiation sources to simulate the effects of radiation ionization and radiation displacement,respectively. The correctness of the model is verified by experimental results. Using this model,the non-uniform characteristics of the gain of each wavelength of EDFA in WDM application under different types of radiation and different temperatures in deep-space radiation environment can be obtained,providing reference for WDM application of EDFA in deep space laser communication.