The invention discloses a physical fusion modeling method for general electromechanical transient information of a photovoltaic power generation system. The method comprises the following steps: (S1) dividing the photovoltaic power generation system into a photovoltaic cell module, a maximum power tracking control module, a DC/DC converter module, a DC linkage module, an inverter outer ring module and an inverter inner ring module according to the function; (S2) building a physical model for the module for inputting physical quantity according to the types of input data at input ends of various modules and building an information model for the module for inputting information quantity; and (S3) fusing the physical module and the information model according to the functional logic relationship among the modules in the photovoltaic power generation system and building an electromechanical transient information fusion model of the photovoltaic power generation system. According to the method, real-time data generated by the photovoltaic power generation system is adjusted and processed in real time through the information model, so that the real-time data is close to a preset reference value; the requirements of different manufacturers on the model universality are met; and the accuracy of the universal model is met.