The utility model provides a tail collision avoidance mechanism of a commercial vehicle, belongs to the technical field of traffic safety and protection, and relates to an anti-collision mechanism of a commercial vehicle. The tail collision avoidance mechanism is characterized in that a hydraulic spring, hanging lugs, an electric control spring, an anti-collision beam and an energy absorption box are included, the hydraulic spring is perpendicular to the ground surface, one end of the hydraulic spring is connected to the anti-collision beam through a bolt, the other end of the hydraulic spring is connected with one hanging lug through a lock pin, and the hanging lug is connected to the bottom of the compartment of the commercial vehicle. The electric control spring is horizontal and perpendicular to the anti-collision beam, one end of the electric control spring is connected to the anti-collision beam, the other end of the electric control spring is connected with the other hanging lug through a lock pin, and the hanging lug is connected to a girder of the commercial vehicle. One side of the energy absorption box is connected with the anti-collision beam, and the other side of the energy absorption box is connected with a vehicle body. The collision process of the rear-end collision of the commercial vehicle and a passenger car is changed to the flexible process from the rigid process, and dangers are reduced. The tail collision avoidance mechanism is obtained by modifying an original tail collision avoidance mechanism of a commercial vehicle, operation is simple and convenient, time and labor are saved, and the tail collision avoidance mechanism has good application and popularization prospects.