The invention discloses a broadband impedance scanning method and system based on a real-time digital simulator. The method comprises the steps that when a power grid system model and a to-be-tested system stably operate, an impedance scanning signal generating and collecting device obtains a configuration file containing scanning signals of a plurality of working conditions, and three-phase disturbance signals of the plurality of working conditions are generated according to start and stop signal instructions of an impedance model identifier; the three-phase disturbance signals of the plurality of working conditions are sequentially injected into a real-time digital simulator, so that the disturbance source generates three-phase voltage disturbance and three-phase current disturbance signals corresponding to the port of the system to be tested; and the impedance model identifier calculates the broadband impedance of the to-be-tested system according to the acquired three-phase voltageand the acquired three-phase current signal. According to the method, the impedance characteristic of the power device in a wide frequency domain range can be efficiently and quickly obtained, and the obtained scanning result provides an important basis for influence analysis of access of various power equipment to a power grid.