The invention reveals a coach vehicle distance early warning system. The system includes a plurality of coach vehicles, each coach vehicle is provided with a vehicle-mounted unit, a road side unit is arranged in a training field, the vehicle-mounted unit includes a positioning module, a vehicle-mounted processor, a warning module and a vehicle-mounted communication module, the road side unit includes a map module, a road side processor and a road side communication module, and the road side communication module communicates with the vehicle-mounted communication unit of each vehicle-mounted unit. Through information interaction between the vehicle-mounted units of the coach vehicles and the road side unit, the coach vehicle distance early warning system judges risks of occurrence of an accident and performs early warning, and prompts a student on a coach vehicle to pay attention to keeping distance with a coach vehicle which enters single-item practice ground in the front, or the student is forbidden from entering the practice ground, and enters the field to practice after the coach vehicle in the front completes practice action, thereby avoiding occurrence of an accident, and improving safety of driving of the coach vehicles.