The conventional graph editing of one-line substation diagrams for a graphical user interface is time-consuming and needs considerable effort. A method for automatic generation of the substation diagrams is described in this paper. In this method, artificial intelligence (AI) frames are adopted for the representation of substations and their network, some expert rules on the layout and drawing of substation buses are accumulated and summarized, and AI rule-based inference techniques are used for branch analysis on different types of buses and drawing of the buses and their branches. A vertical coordinates conversion relationship is obtained to narrow the testing of substation diagram components’ vertical layout. The method has been programmed and applied to two power system analysis programs, one of which is undergoing field test in a transmission system for real time fault diagnosis in northern China.