In this paper, the characteristic temperature is calculated and the load demand is analyzed. Then, the load conditions of typical working days and rest days are selected respectively, and the baseline load of typical working days and rest days is calculated respectively. After considering the impact of economy, business expansion and installation, and account cancellation, the base load of working days and rest days is calculated. Finally, the cooling load of each province is obtained by subtraction of the base load from the actual power load demand of each province on working days and rest days, and the cooling load of the operating area of the State grid can be obtained by summing up the cooling load of each province. At the same time, the variation characteristics of cooling load are analyzed, and the power load, cooling load, sub-industry power load and sub-industry cooling load in summer peak time of a province in China are analyzed in detail. The cooling load during the summer period of kurtosis presents a trend of total increase, uneven time distribution, uneven distribution and variety.