The invention discloses a self-adaptive rampway auxiliary lighting device and a self-adaptive rampway auxiliary lighting method. The self-adaptive rampway auxiliary lighting device comprises a controller, a camera of which the output end is connected to the controller and an execution mechanism connected to the controller, wherein the controller comprises an image processing device which consistsof an image conversion device and a vehicle distance algorithm processing device; the camera is arranged on the front part of a vehicle for collecting video images in front of the vehicle; the execution mechanism is connected with a headlight; and the controller processes images captured by the camera through the image processing device, acquires rampway angle information and controls the execution mechanism to adjust the illumination angle of the headlight according to the acquired rampway angle information. The self-adaptive rampway auxiliary lighting method comprises fives steps for using the self-adaptive rampway auxiliary lighting device. The device can provide sufficient light for a driver when the vehicle runs up a ramp and avoid dazzling the drivers of coming vehicles when the vehicle runs down a ramp. The device and the method can improve the driving safety of an automobile.