For liver segmentation on abdominal CT images, a novel algorithm is proposed which is based on the threshold method and modified GGVF-Snake model. Firstly, the CT image is converted into grayscale by using Window-Leveling algorithm, and then Modified Curvature anisotropic diffusion filter is applied. Secondly, a threshold method is used to obtain the initial contour of liver. Finally, the accurate liver boundary is obtained by using a modified GGVF-Snake model. Experimental results show that the proposed algorithm can be applied to the segmentation of liver on abdominal CT images effectively.