An image processing method for a display device is provided. The method includes steps of: setting one of the multiple pixels arranged as a matrix of the image to be processed as a pixel to be processed, and using the pixel to be processed as a center and setting remaining pixels as reference pixels; obtaining a maximum brightness value and a minimum brightness value of the brightness of the pixel to be processed and the brightness of each reference pixel; determining a relationship of the brightness relation value between the pixel to be processed and the reference pixels and a preset reference value; when the brightness relation value is greater than the preset reference value, setting the brightness of the pixel to be processed as the maximum brightness value, otherwise setting the brightness of the pixel to be processed as the minimum brightness value.