Luminance supplementing method and device for display device, and display device

The invention discloses a supplementing method and device for improving luminance uniformity of a display device, and the display device, wherein efficiency of extracting luminance information of the display device is improved while luminance uniformity of the display device is improved. The luminance supplementing method for the display device includes the steps of firstly, for each sub-pixel, corresponding to the display device, in an input image, obtaining an input gray-scale value of the current sub-pixel and a function relation corresponding to the current sub-pixel, wherein the function relation is a corresponding relation which is determined between the supplemented grey-scale value corresponding to each sub-pixel and the input grey-scale value for the sub-pixel of the display device in advance according to the test luminance value and target luminance value of the sub-pixel under various test patterns with different grey-scale values; secondly, obtaining the supplemented grey-scale value corresponding to each sub-pixel through the input grey-scale value and the corresponding function relation of the sub-pixel, and conducting luminance supplementing on the sub-pixel according to the supplemented grey-scale value.