Abstract: Complex shape decomposition is a commonly used method for image processing，pattern recognition and computer graphics．The traditional decomposition method based on concave points detecting can only separate an area into tiles．In this paper，we present a new method to decomposite a complex area which has stroke-like subareas embedded into strokes．Using a new sub-area constructing algorithm，this method can separate the outline of all Chinese character in GB2312-80 into easy-recognized strokes automatically．