The invention relates to the technical field of stability judgment of an inversion distributed power supply, in particular to a judgment method for grid-connected transient stability of the inversiondistributed power supply. The judgment method comprises the steps of building a droop control model and a grid-connected model of the inversion distributed power supply, inputting transient event information, updating the transient event information after a transient event, and judging the stability of the inversion distributed power supply grid-connected system according to a criterion. By building the droop control module and the grid-connected model of the inversion distributed power supply, whether the inversion distributed power supply is stable after the transient event can be rapidly distinguished; and meanwhile, a factor affecting the stability of the grid-connected inversion distributed power supply can be effectively analyzed, basis is provided for on-line judgment of the systemon the transient stability of the inversion distributed power supply, and a technical support is provided for transient and stable running of the system.