The invention provides a rear lamp control method, a rear lamp control device and an automobile. The method comprises steps as follows: state information of a switch connected with a rear lamp is detected, wherein the rear lamp is one of a position lamp, a backup lamp and a brake lamp; when the state information of the switch connected with the rear lamp is switch-on state information, an output state of the rear lamp is determined; when the output state of the rear lamp is an output failure state, other rear lamps of the automobile are controlled to be turned on. Therefore, when any type of rear lamp of the automobile breaks down, the other types of rear lamps are turned on to replace the rear lamp required to be turned on currently, the automobile behind is reminded of a driving state of the front automobile, traffic accidents are prevented, and the safety risk of the automobile is reduced.