It is shown by analyzing large test data that the empirical formula presented in the paper has higher linearly dependent coefficient , lower average relative error and relative standard deviation compared with the traditional empirical formula of orthoscopic and power function 试验数据表明,本文提出的经验公式比传统的直线式和幂函数式经验公式的线性相关系数更高,且平均相对误差和相对标准差都低。