The invention provides an image processing method, a device thereof, and a display device, and relates to the display technology field. By adopting the image processing method, the problems of the edges of the images such as jags and color cast can be improved. The image processing method is characterized in that a frame of first image data can be acquired, and a row of real pixels on an edge side of a first image is provided with corresponding virtual pixels, and every virtual pixel comprises the sub-pixel of the corresponding real pixel and at least one sub-pixel adjacent to the corresponding real pixel; the first image data can be converted into the second image data, and by aiming at the at least one row of real pixels on the edge side of the first image, the gray-scale value of every sub-pixel of each of the real pixels can be allocated to the sub-pixel of the corresponding virtual pixel, the color of which is the same as that of the sub-pixel of the above mentioned real pixel, and the gray-scale value of every other real pixel allocated to every sub-pixel is remained; and the sum total of the gray-scale values allocated to the same sub-pixel can be used as the gray-scale value of the sub-pixel of the second image data. The image processing method is suitable for the display of the display device.