The invention discloses a method for predicting a line loss rate trend based on a partial pressure line loss model. The method includes the steps of analyzing the loss rate of each part of power transmission of a power grid and constructing the partial pressure line loss rate model; according to the partial pressure line loss rate model, obtaining a calculation formula of the partial pressure lineloss rate and calculating the proportion of partial pressure power selling corresponding to the minimum value of the partial pressure line loss rate; combining with actual power grid data and obtaining parameters of the partial pressure line loss rate model; according to the partial pressure line loss rate model and the resulting parameters, predicting a future partial pressure line loss rate. According to the method, the trend judgment and prediction of the future partial pressure line loss rate are achieved, a power grid enterprise is helped to control future line losses, targeted energy conservation and loss reduction transformation are carried out, and the operating economy is improved.