通过对弧底梯形明渠均匀流基本方程的数学变换，得到其无量纲正常水深的迭代公式，并从数学上证明了该迭代式的收敛性；通过数值计算选取恰当的迭代初值，再经迭代运算，提出了弧底梯形明渠均匀流水深的直接计算公式。实例计算及误差分析表明：在工程实用范围内该法最大相对误差为０．７％，而且克服了以往查图查表法及试算法的缺点，是一种简捷准确的有效方法。 Through the mathematical transformation of the basic equations of uniform flow in the trapezoidal channel, the iteration formula of dimensionless normal water depth is obtained and the convergence of the iterative method is proved mathematically. By numerical calculation, the appropriate initial value of iteration is selected and then iterated The direct calculation formula of uniform flow depth of arc trapezoidal channel is put forward. The example calculation and error analysis show that the maximum relative error of this method is 0.7% within the practical range of engineering, and it overcomes the shortcomings of the previous look-up table method and trial method, which is a simple and effective method.