在测试管段比阻的基础上,提出用几种常用水头损失公式计算旧管段直径、海曾——威廉斯公式中系数C和柯尔勃洛克公式中绝对粗糙度k值的方法.并结合实例进行了计算和验证.结果表明:该方法同时考虑了管径及阻力系数对管网水力计算的影响,使旧管道的计算值更接近实际,因而具有广泛的实用性. Based on the test of the specific resistance of the pipe section, the method of calculating the diameter of the old pipe, the coefficient of the C in the Williams formula and the absolute roughness k value of the Kolblock formula are calculated by using several common head loss formulas. The calculation and verification are performed. The results show that the method considers the influence of pipe diameter and drag coefficient on the hydraulic calculation of the pipe network, and makes the calculated value of the old pipe closer to the actual one, so it has a wide range of practicality.