In the nanometer technology node, the contradiction between high investment and low yield has got more and more prominent, so it plays a very significant role in improving the yield to optimize layout. The COE, Critical area On Edge network, which is a kind of network based on the redundancy material defect with edges expressing critical areas, is constructed in this paper. Vertexes stand for nets of the layout, and edges do short circuit areas existing in nets. By studying the applications of COE in DFM, it is indicated that the COE provides a new way to the research of nanometer node in DFM.