After introducing various uncertain factors including a stochastic initial condition, a stochastic coefficient and a stochastic input term into calculating program of flow profiles in river, a stochastic differential equation is established. 将各种不确定性因素(包括随机初值条件、随机系数和随机作用项等)引入河道水面线的推求过程,建立了计算河道水面线的随机微分方程。