Abstract: A general decoupling method and system for electromagnetic transient simulation of a VSC are provided. The method includes: determining state equations of equivalent circuits and switch state tables of different VSCs; splitting the state equations, and decoupling and delaying capacitor elements and inductor elements to determine split equations; determining a recurrence relation of a state variable group with respect to a time sequence based on each split equation; obtaining a topological structure of a to-be-simulated VSC, and determining a decoupling model circuit; determining a switch state of the to-be-simulated VSC at a current simulation moment, and constructing a final decoupling model circuit; determining an external port voltage based on the final decoupling model circuit; and updating the state variable group at the current simulation moment based on the external port voltage and the parameters of the decoupling model circuit corresponding to the switch state.