Picking is an important part of the distribution center operation process, but it consumes a lot of time and manpower. In recent years, many logistics companies have applied AGV systems, and want to transform traditional logistics into automated logistics to solve the problems of time and manpower consumption. However, the AGV systems are often applied with investing a large amount of import costs but without appropriate planning. It may cause counter-effects, such as idle resources, insufficient resources, and AGV traffic jams. All of the above problems may affect the picking efficiency of the AGV systems. Therefore, this study adopts the FlexSim system simulation software as a tool to simulate the situation of the distribution center using the AGV system for the picking process, and explore the impact of changes in the number of vehicles and dispatch rules on the system performance.