Crowd simulation has been widely used in virtual reality, entertainment and many other fields. The research about rendering and behavior control has made some progress now. Real-time crowd interaction can make the simulation more attractive and express users’ ideas better, so it is becoming increasingly important in crowd simulation. This paper presents a new GPU-based crowd interaction approach, which is extremely efficient orienting to group interaction. In this approach, the behaviors of crowds are represented as all kinds of primitives. All the primitives constructed will be rendered into a discrete event map in real time and the map will be used to guide the interactive behaviors of crowds. The experiments show that using our approach, we can simulate tens of thousands of crowds in real time with a variety of interactive events at the same time.