Skeletonization is an important procedure of automated palmprint identification system based on the characteristic of minutiae. Skeleton acquired by traditional thinning algorithms will produce many spurious minutiae which are caused by spurs and misconnections between ridges. The excessive erosion is also a common problem in thinning algorithm. Moreover, unit skeleton cannot be produced by some of these algorithms. In this paper, we introduce a thinning algorithm, which is based on Rotation Invariant Thinning Algorithm introduced by Ahmed and Ward [1] (A-W). The proposed method can solve the above problems. The experimental result shows some skeletons from local regions of palmprint images and running time of the algorithm, which shows that the proposed algorithm can achieve better performance without reducing efficiency.