High dose irradiation by ionizing radiations kills effectively micro-organism pathogen in foods, in order to ensure food safety and prolonged shelf life. In this paper, fresh pork loin samples were treated with methods of protein enzyme inactivation at 72℃, vacuum packing and freezing temperature irradiation of ,60,Co γ-rays, so as to minimized effects of radiation chemical reactions during the radiation processing. SDS gel electrophoresis and other analyses were done on the irradiated samples. The results show that up to 45kGy irradiation at (-20±5)℃ the samples generates no significant impairment in the protein quality, despite minor structural changes in the proteins. The amino acid contents remained almost the same, whereas retentive rates of vitamin B1 and B2 were about 22% and 61%, respectively.