The invention discloses a method for judging and processing wind farm power prediction input data. The wind farm power prediction input data is historical data of the wind farm, and contains normal data, damaged data and distorted data, wherein the damaged data and the distorted data has harmful effect on the reliability of a sample set of training data of a wind farm power prediction mode, and further influences the precision of the wind power prediction. The invention provides a preprocessing method for wind farm historical data, in the method, the normal data and the bad data in the data are distinguished, and the damaged data or the bad data in the data is increased or changed, so that the reliability of the sample set of the training data of the prediction model is enhanced, and the accuracy of wind farm power prediction is improved.