Abstract: Newborn bovine serum was irradiated respectively by ⁶⁰Co at the average dose rate of 60 Gy/min and 600 Gy/min and by electron accelerator at the average dose rate of 300 kGy/min, then the bovine serum protein biochemical properties and the micro structure were researched to discuss the effect of high dose rate on inhibiting the denaturation of bovine serum protein during the irradiation sterilization process. The results show that compared with the no irradiated bovine serum, protein turbidity, fluorescence intensity of hydrophobic amino acid and exothermic peak time increase respectively from 0.742, 24.1 u and 16.5 min to 0.802, 99.3 u and 17.2 min, but the concentration and exothermic peak temperature decrease from 0.473 and 76.4 ℃ to 0.444 and 74.5 ℃. SDS-PAGE reveals that the protein content of 175 kDa and 58 kDa in 600 Gy/min of ⁶⁰Co irradiated bovine serum were significantly higher than that in low dose rate irradiated one. The precipitation from irradiated bovine serum shows dense network structure in SEM images, and the soluble fraction presents fragments and globular body mixed morphology structure. The globular shape is not prominent for the sample treated by low dose rate. High dose rate is found to inhibit the effect of irradiation on the denaturation of bovine serum protein, and the effect of 600 Gy/min ⁶⁰Co source is the most obvious in the three types.