Abstract: The physical distribution network flow problem which is about transferring cargos from supplying points to deman ding points by some carrier like truck or ship etc is proposed．The goal is to decrease the distribution cost．A mixed integer programming model was used to describe the problefn．Taking network simplex method ，Lagrangian relaxation and heuristic methods as the main research method s，a approximate solution was got．

Key words: mixed integer programming, Lagrangian relaxation, network simplex method , heuristic

摘要： 考虑物流配送中的网络流问题，即由某些供应点向各个需求点通过某种运输工具(货车、轮船等)供应货物的 问题，目的是尽可能的降低配送成本．通过一个混和整数规划模型来描述该问题，利用网络单纯形法、拉格朗日松弛 算法以及试探法为主要研究方法，有效地得到该问题～个近似程度较高的可行解．

关键词: 混和整数规划, 拉格朗日松弛, 网络单纯形法, 试探法