The gelatin was irradiated by 60Co-γ with the dosages of 0-527kGy and the parameters including viscosity, gel strength, protein component and molecular weight were determined immediately. The results showed that the intrinsic viscosity, relative viscosity, gel strength, molecular weight, and melting point decreased with the increasing of the dosage. The content of high molecular weight components decreased. The number average molecular weight and weight average molecular weight were in the range of 7839-1061 and 32444-36506. The polydispersity was between 336 and 445. Compared with the intact gelatin, the irradiated one had the wider distribution of molecular weight and higher gelling temperature, the range of which was 398-427℃. Moreover, the membrane was smoother. The results indicated that the main reaction of gelatin during the irradiation was degradation under the condition of limited water and oxygen.