In view of the complex change of the variable power supply voltage, this paper lucubrates optimization method of advanced metering infrastructure outage site diagnosis which is available for the construction of strong smart grid, put forward optimization strategy for diagnosis at the scene of an outage and multiple equipment two-dimensional delta-T judgmental algorithm. The outage diagnosis function based on the comparison between outage and resumption data of acquisition terminal and smart meter is realized, which could judge the attribute of outage incident and report to the master station. The test results show that, acquisition terminal designed to follow the functional requirements can accurately judge the attribute of the outage incident based on outage and resumption data of acquisition terminal and smart meter, and report correct judgment result to master station, meeting design requirement.