The present invention provides a light compensator, a shading tape, a backlight module and a display device. The light compensator comprises a first surface on which at least one recess is provided, wherein, when the light compensator is arranged above an edge of an optical element, the first surface faces a light-exiting surface of the optical element, and a surface of the recess is capable of converging light irradiating thereon and reflecting the light toward an area with low luminance on the light-exiting surface of the optical element. The above light compensator can perform light compensation on areas with low luminance on the light-exiting surface of the optical element, enhance the luminance of the areas with low luminance on the light-exiting surface of the optical element, and achieve luminance uniformity of respective areas on the light-exiting surface of the optical element.