To evaluate the influence of touriquet ischemia and hyperthermia on the radiation effect of skin , the experimental study was undertake using a total of 344 mice.A single dose of irradiation form 2000 rads to 8000 rads was delivered on skin of mouse tail after hyperthermia of 4$0^{circ}C$ to 42 $^{circ}C$ with or without tourniquet application in various subgruops. The results are summarized as follows ; 1. Tourniquet ischemia during irradiation caused radiogprotective effect. 2. Hyperthermia before irradiation induced raiosecsitizing effect, which was increased with temperature elevation of hyperthermia. 3. In combination of tourniquet ischemia and hyperthermia, evident radiosensitizing effect was noticed. This enhancing effect on irradiation was greater than the effect inhyperthermia only. In could be suggested that the combination of tourniquet application and hyerthermia might be introduced in clinical raidotherapy after trial of clinical experiemtns on applicable type and suitable locat on of tumors.