The space-based photoelectric imaging system has a great effect on recent high-tech local wars.However,the importance and inherent frangibility of the space-based photoelectric imaging and remote sensing device make problem of safety and protection more serious.In this paper, frangibility and manifold threats against space-based photoelectric imaging and remote sensing device, such as various plat- forms based anti-satellite laser weapons, kinetic kill vehicles, high power microwave weapons, are presented. In allusion to these threats, several defend technology, countermeasure and corresponding methods including space-based self-protection warning, multi-spectral artificial target, multi-spectral camouflage and smoke interference, photoelectric sensor reinforce, increasing the ability of flexibility of photoelectric imaging platform, carriage of self-protection weapons and so on, are analyzed, in which up to date technologies of laser radiation for space-based photoelectric imaging sensor protection, for example liquid crystals for protection,are emphasized. Some advice for new concept and low cost defend technology development are presented.