Abstract: In computer vision system,fuzzy c-means algorithm plays an important part.First,this paper presentsa formal definition of fuzzy segmentation.Based on this,fuzzy c-means algorithm is modified.Then,weput forward a fuzzy split-cluster algorithm:FSC,which can determine automatically grouping number c.Compared with the fuzzy c-means algorithm,FSC algorithm will be able to increase the calculation speedgreatly.We believe that FSC algorithm is of gteat value to us.