Abstract: It is a frequently used method for weather forecasters to use temperature numerical forecast grid value of EC 850hpa as reference data to predict short-term and medium-term maximum and minimum temperature.Three kinds of maximum and minimum temperature PP method modification forecasting projects according to seasons, precipitation and 850hpa temperature variation, were put forward.Comparison analysis of the three projects was done to find out the best method in order to improve the forecasting precision of maximum and minimum temperature on the original basis.