The invention relates to a device and method for improving ground fault identification through transient characteristics of fault duration. The device comprises three groups of functional units whichcommunicate with each other, a plurality of zero-sequence current measurement units for line zero-sequence current monitoring, a zero-sequence voltage measurement unit and a fault positioning unit. Therefore, time-sharing transient characteristic identification and extraction during the fault duration can be carried out. Meanwhile, a plurality of time-sharing features are used for comprehensive judgment, so that the accuracy is high.