The "early warning device" automatically establishes a wireless digital protection network at the accident site, and the "front end of the early warning device" inserted on the cone uses a red warning light pattern to warn and induce vehicles to bypass the accident site. When a vehicle on the road accidentally breaks into the warning area of the accident site and knocks down the cone, the alarm signal is transmitted through the on-site wireless digital network, and the intrusion alarm is placed at the accident site. The sound and light alarm will warn the on-site staff to avoid the intrusion in time. Vehicles ensure the safety of personnel and avoid secondary accidents.