Abstract: In this paper, a new digital picture representation——EQT representaion is proposed. EQT stands for Extended Quadtree. In the view of data compression it emphasizes the properties among pictures. In the view of PDB, it stores the pictures with redundancy control. For the four experimental binary pictures, the storage requirement is only about 39 percent of that of QT representation. By the way, it is worth saying that such a structure can be used for dynamic tracking.