In this paper, a new technique of daily peak load forecasting is proposed. At first, we propose Non-linear correction T method as improvement technique of T method that is one of the multivariate analysis techniques, called MT system, suggested in Quality Control. Moreover, we examine the daily peak load forecasting technique, which is based on data in the last year on a forecasting day, by T method and Non-linear correction T method. Furthermore, we examine the technique, which is based on the data of most recent several weeks of a forecasting day, by the T method and Non-linear correction T method. In addition, the effectiveness of the proposed method by comparing the multiple regression analysis is discussed.