Abstract: To counter the roughness interprolation problem about computing water surface-probile in hy-draulic and waterway engineering, this paper has discussed linear method of interprolation. And, twointerprolation method suit for known roughness of one of many discharge were given. By calculatingfor the three methods, the results shows that the method of considering bed roughness and bank rough-ness sepuarately is the best method of interprolation.

Key words: rougness, the best method of interprolation, variable of interprolation

摘要： 本文针对水利或航道等工程上计算水面线时，遇到的不同计算流量时的糙率插值问题，对常用的直线插值方法进行了讨论。同时，提出两种适用于已知一级流量的糙率和巳知多级流量的糙率的插值方法，并经过三种插值方法的实例计算和比较，结果表明：河床、河岸糙率分离法（插值法Ⅲ）为最佳糙率插值法。

关键词: 糙率, 最佳插值法, 插值变量