The invention discloses an online discrimination method and system for the wrong wiring of a three-phase four-wire metering device, and the method comprises the steps: measuring phase voltage effective values, phase voltage phase sequences, phase current effective values, phase current phase sequences, reactive power and power factors of a first element, a second element and a third element in thethree-phase four-wire metering device according to a power utilization collection system; judging the wiring of the metering device according to the phase voltage effective values, phase voltage phase sequences, phase current effective values, phase current phase sequences, reactive power and power factors of the first element, the second element and the third element, and recognizing the wrong wiring in the metering device. The beneficial effects of the invention are that the method achieves the online discrimination of the wrong wiring of the three-phase four-wire metering device based on aconventional power utilization information collection system, so as to achieve the intelligent discrimination of the wrong wiring, and reduce the workload and safety risk of onsite verification.