Abstract: A new method for region representation--P-quadtree representation is proposed in this paper. Compared with quadtree representation, the average space saving of P-quadtree representation is about 94%. Various operations can be performed on P-quadtree representation as fast as on quadtree representation. Furthermore, the primitive by primitive operation mode of the P-quadtree representation makes it more efficient. Actually, P-quadtree is a promising data structure for image processing systems based on microcomputers.