Abstract: Behavioral simulation plays an important role in many scenarios,such as emergency evacuation and intelligent control.Most of these applications focus on single individual movements or group aggregation behaviors,while less attention is paid to behavioral interactions among peers.In order to more realistically simulate the interactions among peers,this paper studies the dynamic formation of peer groups,and the diversity and efficiency of evacuation behaviors from the cognitive psychology of peers,the strength of social relations and the consistency of viewpoints.First,a general framework of peer relationships is constructed based on asymmetric intimacy,including the relationship between intimacy relationship modeling and environmental familiarity.Then,the problem of dynamic formation of peer groups is studied by employing the calculation method of asymmetric intimacy.An improved leader-follower model is proposed in conjunction with environmental familiarity to simulate peer evacuation behaviors.Finally,the Unity3D engine is adopted to simulate the companion behaviors of the peers in several scenarios,e.g.,basketball court,supermarket,park,etc.,and the proposed method is compared with the symmetric intimacy method and the cluster system method to testify the efficiency of peer aggregation.The interaction behaviors of 200 peers were simulated in a scene with a resolution of 80×80.The average frame rate was 46.8 frames/s,the average peer group aggregation efficiency was 87.3%,and the average companion interaction time was 4.78 s.The experimental results show that the asymmetric-intimacy-based leader-follower behavior simulation method can concrete the macro group behavior and effectively simulate the dynamic peer group.The simulation effect is diverse and efficient.