This paper presents a new topology search algorithm for identifying the status of connection between electrical devices through an automatic analysis of the terminal coordinates of primitive objects in a power network. The basis of topology search algorithm， a common information model（CIM） based graphical system developed with the graph-data integrated method can effectively unify the electrical parameters and visual characteristics of the electrical devices. By means of the canvas grid， the integer coordinates of device terminals are used as the primitive numbers of electrical nodes. The topology search efficiency can be significantly improved by regarding the connectivity devices as virtual disconnect switches prior to merger of the nodes. The algorithm proposed is suitable for various device primitives， geometric primitives and additional unknown primitives， which can make the time complexity of topology search from nonlinear N2to linear N . Actual applications indicate that when there are hundreds of device terminals， the topology search speed can be increased by one or two orders of magnitude，and the more the device terminals there are， the more significant the increase will be.