A system and method to test integrity of an electricity power supply network in an aircraft is disclosed. The system comprises: a current injector for connection to an output point of one or more phase line forming a test circuit with an electricity generator, the current injector configured to inject a test signal through the electricity generator in the test circuit; a current measurement test probe for installation in the test circuit to measure intensity of the injected test signal current; and a processing unit to connect to the current measurement test probe and to a set of input and output current measurement probes associated with the phase line to acquire current intensity measurement signals output by the current measurement test probe and by the set of input and output current measurement probes, and to determine electricity indicators representative of the integrity of the electricity power supply network.