Based on the principles of organizational optics, the noninvasive tissue oxygenation saturation monitor was developed. The monitor was used to continuously monitor the changes in regional oxygen index of the thigh vastus lateralis in 101 volunteers, who performed an incremental intensity exercise on bicycle ergometer. Among the volunteers, 42 are athletes, 25 are patients whose spleens are asthenic, and the other 34 are controls. Hemoglobin concentration (ｃtHb) measured was heavily influenced by the thickness of fattiness; however, regional oxygen saturation (rSO2) was influenced much lightly. In the experiment, following increasing exercise intensity of the volunteers, their ｃtHb increased, while their rSO2 decreased. When the volunteers stopped the exercise, both of their ｃtHb and rSO2 increased quickly. The results showed that the regional saturation of oxygen of muscle was closely correlated with physical performance. The changes of regional saturation of oxygen of muscle can be used to evaluate the balance between supply and consumption of oxygen, and quantitatively assess the capability of oxidative metabolism in muscles.