Abstract: Due to the service efficiency and the demand expansion in logistic network,we need to adjust weight of arcs (distribution time) to optimize the service of the network,in which the facilities are located. Two factors:operation cost and improvement cost are considered in this problem.In this paper,the cost trade-off model based on the network improvement is described. We present strongly polynomial time algorithms to solve this problem in a tree by transforming it to the minimum cost flow problem with auxiliary network. Finally,we compute an example and give trade-off analysis.

Key words: facility, operation efficiency, improvement cost, trade-off model