This paper describes an improved thinning algorithm for binary images. We improve thinning algorithm from the fundamental properties such as connectivity, one-pixel width, robust to noise and speed. In addition, in order to overcome information loss, we integrated the contour and skeleton of pattern and proposed the threshold way. Some fundamental requirements of thinning and the shape of pattern are preserved very well. Algorithm is very robust to noise and eliminate some spurious branch. Above all, it can overcome the loss of information in pattern. Experimental results show the performance of the proposed algorithm.