In order to test imaging performance of an optical remote sensor in complex space environment, a space environment simulation system with a wide rang irradiation and high contrast is designed, including a solar simulator and a dark target simulator. According to the radiation characteristics of sunlight and earth reflection light, a wide range of solar simulation irradiance is achieved by adjusting xenon lamp current regulation and using attenuation chips. A dark target simulator is designed to simulate the weak observation target, based on the analysis of the scattering characteristics of the material and the design of the reasonable structure. The experimental results show that the irradiance range can reach 0.4~1 260 W/m2 in the 1 000 mm×1 000 mm irradiation area, and the irradiation uniformity can reach ±4.82%.The extinction ratio of the dark target simulator can reach 1×10－7 .The device can solve the problem of the quantitative test of imaging performance for the dark target in the space with strong background light, which provides a reliable platform for the performance test of remote sensor.