Abstract: An improved quadtree structure based on storing ascendant attribute is proposed,which is called ascendant quadtree.A recursion algorithm of constructing ascendant quadtree that implement a bottom-up process is also presented.A lot of experiments were carried out to demonstrate the memory-efficiency and algorithm advantages of the proposed method.The results for different scales and different complexities show that the proposed quadtree structure can obviously reduce the total of nodes and has a 69% compression improvement compared with the constant bit-length linear quadtrees,and has a better practical value and application prospect.