The invention relates to the technical field of power monitoring, and particularly discloses a judgment method and system for ammeter and transformer relations. The judgment method comprises the following steps: reading a transformer clock of a transformer in a district and a transformer outage event record file; reading an ammeter clock of the user's ammeter and the ammeter power failure event record file; judgingcorresponding relation between the transformer in thedistrict and the user's ammeter according to the transformer clock, the transformer power outageevent record file, theammeterclock and the ammeter power failure event record file.According to the judgment method and system for the ammeter and transformer relations, the ammeter and transformer relations can be accurately judgedwith little trouble and effort.