The invention provides a distributed photovoltaic power prediction method based on online modeling, which comprises steps: I, a distributed photovoltaic power prediction general model is built; II, online data processing is carried out; III, the distributed photovoltaic power prediction model is corrected; and IV, the distributed photovoltaic power prediction value is obtained. Based on the online data processing method, quick distributed photovoltaic power prediction model building can be realized, accumulation of a large amount of historical data is not needed, the algorithm generality is high, and the method is applicable to any distributed photovoltaic power stations.