The preparation technology and performance evaluation of flexible composites were studied for the new flexible solar blanket used in deep space exploration missions in China. The results show that the molded polyimide fiber reinforced silicone rubber can meet the demands of flexible solar blanket. The automatic coating process can achieve the uniform and thin coating of high viscosity silicone rubber on polyimide film. The comparative test show that the silane coupling agent can improve the T-peel strength of flexible solar blanket，but reduce its flexibility at low temperature.