This paper summarizes the research status and the latest achievements of the event-based control system. It mainly introduces the various types of the event driven communication mechanism and research directions of event-triggered control, including the different methods of modeling, co-design schemes for controller and event generator. It focuses on the modeling method of time delay system, and the closed-loop event-triggered control system is modeled as a time-delay model. In addition, the influence of the network-induced factors on the event triggering mechanism and some applications are also explained. Finally, relevant questions in current research are presented, and some open problems that need to be solved in the future are pointed out.