We obtained the flock image distributed in the water using the image input device, and the size and distribution ratio of flocs were obtained using image processing algorithm. the image input device provides the user with the image in real time in the water, and the user analyzes the flock information using the developed image processing algorithm. Since the study of floc analysis using image processing technique is not available in Korea, this study is different from conventional floc characterization studies such as ja-test and IPDA. Not only was it possible to elucidate the characteristics of flocs in a shorter time.