Abstract: In the traditional measurement of blood oxygen, amended Lambert-Beer Law is used to calculate the oxygen percentage in the blood. On the one hand, results will be acquired slowly because of the divide operation. On the other hand, amount of precision will be lost because of the errors by using ratio, which leads to the low accuracy results. In order to solve this problem, multiple regression analysis is used in this paper to measure and evaluate the oxygen percentage in the blood. Results show that, compared to the ratio, the new method has an obvious advantage and can be realized by hardware more easily.