从求解一维圣维南方程组的Preissmann 4点隐式差分格式出发, 建立了一维河网及渠网数学模型，并对计算中所涉及的一些关键技术问题进行了较为详细的阐述。利用模型对树状渠网的恒定流及复杂的环状渠网和河网的非恒定流对模型进行验证。验证结果表明，水位和流量过程计算值与Islam的计算值吻合较好，各渠道的流量分配计算结果精度也较高，为河网及渠网的水量调度提供了一个较为简便实用的工具，为建立渠网及河网的综合水质生态数学模型打下基础。

Based on Preissmann implicit scheme for one-dimensional Saint-Venant Equation,  the mathematical model for one- dimensional river networks and canal networks is developed and the key issues on the model are expatiated particularly in this paper.  This model is applied to simulating the tree-type irrigation canal networks and complex looped canal networks.  The results of levels and flows and discharge distribution between the branches agree with the data from Adlul.  This model is a simple and practical tool for water resource regulation of irrigation canal networks and river networks.  These results show the application value of this model is to set up ecological numerical model of water quality in river networks and canal networks.