This paperpresents a fully automatic segmentation method of liver CT scans using fuzzyc-mean clustering and level set. First, the contrast of original image isenhanced to make boundaries clearer; second, a spatial fuzzy c-mean clustering combining with anatomical prior knowledge is employed toextract liver region automatically; thirdly, adistance regularized level set is used for refinement; finally, morphologicaloperations are used as post-processing. The experiment result shows that the method canachieve high accuracy (0.9986) and specificity (0.9989). Comparing with standard level set method, our method is more effective indealing with over-segmentation problem.