Logistics system, like other systems, is an interrelated and interactive whole. The logistics system consists of seven subsystems: warehousing, distribution, transportation, packaging, loading and unloading, distribution and processing, handling and logistics information. There is antinomy between them, that is to say, there is a trade-off between them. At this time, the problems of service level and logistics cost are inevitable. Therefore, the design of logistics system should not only consider the relationship between subsystems, but also pay attention to the proportion of cost and service.