This paper presents an application of a digital camera and the techniques of digital image processing (DIP) in automatically analyzing the uniformity of paint color coating on a wall surface. The DIP methods such as filter process, equalization and normalization were individually considered to enhance the quality of test images. The experimental results demonstrate that the combination of median filter and normalization of HSV color space are helpful for promoting the reliability of analyzing the uniformity of paint color coated on a wall surface, which also shows the practicability of the presented method.