Based on the rule that the varieties of diffuse reflectance light intensity ( Iglu/ Inet) is linear to the radial distance, we define a way to locate the floating-reference position point by linear fitting after measuring the light intensity in different location with great distance. 根据漫反射光强的变化(Iglu/Inet)随着径向距离呈直线分布的规律,我们找到了一种大间距测量直线拟合的寻找浮动基准位置的方法。