A method of image processing and a device thereof are provided in the present invention. First, an image having a plurality of regions is received, wherein each region comprises a plurality of pixels. A contrast process is performed on each region and a respective local curve of each region is analyzed, wherein the local curve is a corresponding relation between the gray-level values of the pixels in each region before and after the contrast process. Next, the gray-level value of one of the pixels in a boundary between one of the regions and the neighboring region is adjusted according to the respective local curves of the one of the regions and the neighboring region. The local contrast process towards to each region is performed for enhancing the image. Therefore, not only can the features be obvious, but the non-uniform area in the boundary between the regions also can be smoothed.