Abstract: The segmentation of intima and adventitia of Common Carotid Artery(CCA) in ultrasound transverse images is critical,and the results can be used for qualitative estimates and quantitative measurements of plaque size,thickness and shape．Firstly the adventitia was segmented using Local C-V model and the intima was segmented using C-V model．Distance limitations item was proposed to limit the evolution of the intima,and Sparse field method(SFM) was used to improve efficiency of the level set method．The result was analyzed and compared by full-orthogonal method (FOM),ray method and Dice index．The results indicated that the LCV model can effectively segment the adventitia of the caro-tid artery；C-V model can effectively segment the intima；Improved methods can increase the speed of the program and improve the accuracy of segmentation of the intima and adventitia．

Key words: Biomedical engineering,Image segmentation；Carotid ultrasound images,Level set,Local C-V model