In complex systems, objects often need to communicate with each other frequently. If objects directly reference and depend on each other, the system will become complex and difficult to maintain. In order to solve this coupling problem, the Mediator Pattern came into being. The Mediator Pattern introduces an independent mediator object to manage the interaction between objects, thereby reducing the direct dependency between objects and making the system more flexible. This article will introduce the concept of the Mediator Pattern, the difference from other similar patterns, and the problems it solves.