This review describes the modes of mice radiation injuries induced by soft X-irradiation under various conditions and the protective effects of several kinds of substances on these injuries. The models of radiation injuries in this study were bone marrow death after lethal irradiation, skin damage induced by irradiation with long length soft X-ray and leukocytopenia in the peripheral blood after sublethal irradiation. Two bioassay methods were established for the survival effect on the lethal irradiation and protective potency on the skin damage induced by soft Xirradiation. The protective potencies of various sulfur compounds, related compounds of ferulic acid, nucleic acid constitutional compounds, crude drugs and chinese traditional medicines were determined and then many effective drugs were recognized. Effective components in the methanol extracts of Cnidii Rhizoma and Aloe arborescens recognized as radioprotectable were fractionated. As a result of these studies, it was observed that the active principles in Cnidii Rhizoma were identified as ferulic acid and adenosine. The scavenge action of active oxygens, a protective effect on the damages of deoxyribonucleic acid and superoxide dismutase by in vitro soft X-irradiation were evaluated as radiation protective mechanisms.