The　segmentation　of　tongue-coating　images　is　very　important　to　computer-aided　traditional　Chinese　medicine　(TCM)　clinic　diagnosis　system.　By　now,　algorithms　for　this　segmentation　are　in　low-accuracy　or　high-complexity.　Upon　the　edge-gradient　feature　of　tongue-coating　images,　a　new　segmenting　method　is　presented　in　this　paper,　which　combines　edge　and　region　processing　technologies.　With　the　new　method,　the　multi-scale　morphological　gradient　images　of　the　original　images　are　taken　firstly,　and　then　watershed　algorithm　is　used　to　segment　them　so　that　tongue-coating　images　are　separated.　The　following　experimental　results　show　this　method＇s　effectiveness　and　efficiency.