Abstract: In order to solve the existing problems in current researches on the Snake models of point cloud, a Snake model of point cloud using balloon force is put forward.In this model, the balloon force is extended from 2Dimage to 3Dpoint cloud to design external energy.The model classifies point cloud into feature points and non-feature points according to curvature.Besides target contour, noises are contained in feature points.The external energy has different motion patterns to different point patterns:On one hand, the external force energy will force the contour point to move to the target contour if it is not a feature point.Snake can converge correctly even if the initial contour is far away from the target contour.On the other hand, the external force energy will make the contour point fixed or oscillate if it is a feature point.When the contour point is a noise, the motion of neighbor nonfeature points will force it move off the noise region, this means noises can be removed in the model.Experiments show that the proposed model is insensitive to the position of initial contour and can be less affected by noise points.