The invention provides a distributed photovoltaic system abnormity early warning accuracy calculation method based on an ROC curve. The method comprises the following steps: step 1, constructing a binary classification model of a distributed photovoltaic system abnormity early warning result; step 2, establishing an ROC space according to the binary classification model; step 3, describing the coordinate of each threshold value of the abnormal early warning model in an ROC space to form an ROC curve of a specific model; and step 4, calculating the area under the ROC curve by adopting a trapezoidal method, namely the AUC, and using the AUC as a calculation method of the abnormity early warning accuracy. The method is based on the ROC curve; an accuracy index calculation method of the distributed photovoltaic system abnormity early warning model is defined. According to the method, the problem of the accuracy measurement of the imbalance classification problem is solved, only 2% of abnormal conditions can be avoided in the operation period of the distributed photovoltaic system, and the measurement error that the accuracy measurement is still 98% after all early warning models are normal can be avoided, so that the accuracy of the abnormal early warning model can be described more perfectly.