The invention discloses an automatic control device for automotive rear-view lamp light. The automatic control device comprises a signal collecting module, a control module and an executing module; the signal collecting module is a photosensitive sensor and is used for collecting an illumination intensity signal outside an automobile; the control module is connected with the signal collecting module, composed of a regulating part, a switch part and a relay RL and used for controlling starting and stopping of the executing module; the executing module is connected with the control module, is a rear-view lamp L and is used for providing illumination. According to the automatic control device for the automotive rear-view lamp light, automatic control over the rear-view lamp light in night driving is achieved through the additionally-arranged rear-view lamp and corresponding software and hardware design, and then the night driving safety is improved.