Firstly, based on the conventional observations at forty-two meteorological stations in Qinghai Province, initial guesses of maximum and minimum temperature are made with the statistic method and the forecaster′s program. Secondly, the initial ones are objectively modified as combined with numerical forecasting product and real time observations. Finally, the forecast of the maximum and minimum temperature are given. As a result, an objectively forecasting method of the maximum and minimum temperature adapting to Qinghai Province is developed.