The traditional skeletonization algorithms based on distance transform can not guarantee the connectivity property, so saddle points should be added to solve the connectivity problem. However, these methods are complex and inaccurate, and saddle points can hardly be extended to 3D case. In this paper a novel method was presented, the skeleton obtained by growing from the skeleton seed with 1 pixel width restricted by distance transform, and the connectivity was assured by the growing process. Experiments show that the growing process is a skeleton evolvement from coarse to delicate, and the hierarchical skeleton can be easily achieved.