The invention discloses an emergency brake distance judgment system and method based on a following motorcade. The problem that because when heavy goods are loaded in a cargo compartment, goods are prone to moving forwards to damage the head of a vehicle in the emergency brake process, safety accidents are caused is solved. The system comprises brake distance judgment devices arranged on vehicles of the following motorcade. Each brake distance judgment device comprises a control unit connected with the control system, one or more pressure sensors arranged on the inner wall of the front portion of the compartment, and an acceleration sensor arranged on the body of the corresponding vehicle and connected with the control unit, a distance sensor, a storage unit and a gyroscope are connected to the control unit, and the pressure sensors are connected to the control unit. By means of the system and the method, the speed change rate is effectively regulated through the control unit during emergency brake, the situation that safety of drivers is influenced when goods move forwards during emergency brake is prevented, the protection capacity is enhanced, and meanwhile the position with the largest forward movement pressure can be effectively detected.