This paper was aimed to study the effects of Cobalt-60 gamma ray irradiation on Albino rat blood cells and the activity of enzymes were measured using blood cell auto analyzer (Cell-Dyn 900) and enzyme autoanalyzer (Gilford 3500) respectively. Cobalt-60 gamma rays those are grouped into 200R, 400R, 600R, 800R, 1,000R, 1,200R, 1,300R, 1,400R, 1,500R and 1,600R to the rats of male and female and measured the numeral varieties of blood corpuscles of the rats and the active varieties of enzyme of acid, alkaline phosphatase (ACP, ALP), lactic acid dehydrogenase (LDH), glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase. (GPT) those came out after 1, 3, 5 or 7 days. The results are summarized as follows: 1. In both case of male and female, the numeral varieties of the erythrocytes, in the 200R group of irradiation showed the minimum value in the 3 days group and a tendency of increase in the 5 and 7 days groups, while the numeral varieties of the leucocytes in every groups of irradiation showed a tendency of a rapid decrease after a day. The numeral varieties of the blood platelet in both case of male and female didn't show generally any great change in a day and 3 days groups, but showed a rapid decreasing appearance after the 5 days. 2. In both case of male and female, the activities of ACP were on the decrease gradually after 3 days of the irradiation and the activities of ALP were on the decrease after 5 days. Similarly in both case of mate and female, the activities of LDH showed the decrease after 3 and 5 days, and the phenomenous of GOT showed an appearance of increase in a day, but decreased after 3 days. As for the GPT activities couldn't find any great change in the male rats in comparison with the control groups, but in the female rats a tendency of the increase in 600R, 800R, 1,000R groups after 3 days. 3. In the case of the irradiation of high quantity of ray more than 1,200R, all rats died after 4 days, and by the irradiation of 1,600R all rats died after 3 days, and it showed the sensitive response of a living body to the irradiation of high quantity.