As complex cyber-physical systems, connected vehicle systems are composed of multiple interacting intelligent agents within traffic environments. In this demonstration, a lightweight multi-agent based testbed is presented for evaluating connected vehicle systems. Miniature smart vehicles and quadrotor vehicles are developed as the multi-agent components, which are equipped with embedded processors, ZigBee radio modules and WiFi modules as well. Through cooperative communication, collaborative control and video detection, the multi-agent system can realize the information interaction between air-to-ground, vehicle-to-vehicle, and vehicle-to-roadside. This research is beneficial to develop more intelligent connected vehicles in the near future.