In the segmentation of complex region,aiming at it that the traditional Snake Model can not converge the concavity district and some other weeknesses,we make improvement for the traditional Snake Model through the two aspects,one hand increasing one energy item created by doing work,another hand adopting Greey algorithm in two stages.The result shows that the improved Snake Model can quickly converge the concavity region and the more complex region,and has decreased the dependence of the result of segmentation to the initial value and the influence of noise point to the boundary.