This chapter discusses the research on storing solar energy principle by the ZnS thin film. This chapter introduces ZnS thin film storing solar energy. This film can store solar energy and radiates visible light without photoelectric and photothermic middle transformation process. This method is new one to use solar energy.This chapter illustrates that, in use of solar energy, the most disadvantage factor is its discontinuity. In the overcast and rain days or on the night, without sunshine, utilization system of solar energy can stop working. To overcome this defect, usual method is using photoelectric and photothermic transformation to story solar energy. But because efficiency of the photoelectric and photothermic is low and cost is high, the storing solar energy problem become one of the most essential problem which must be solved.