The invention discloses a primary system wiring diagram automatic generation method based on substation specification description. According to existing engineering schemes, a system specification description file is analyzed, a corresponding model is generated in a database, a primary wire diagram is drawn manually by an engineer, and diagram-model association configuration is performed. According to the method, types and wiring modes of all intervals of a substation are automatically recognized based on a substation system specification description file, and a primary system wiring diagram is automatically generated according to a primary system topological structure and relevant element types obtained through recognition in combination with a multi-scale iterative placement algorithm containing a voltage grade scale, an interval scale, a primary equipment scale and a connecting wire scale. Through the method, the problem that a primary system wiring diagram cannot be acquired in a current intelligent substation automatic system and must depend on manual drawing is solved; automatic association configuration of the diagram and the model is also realized after automatic diagram generation, the possibility that an error occurs due to manual configuration is lowered, and the configuration efficiency of the substation automatic system is improved.