GDP, as an important economic development measurement index, is important to be predicted. By using Chongqing as a study object, by exponential smoothing method in time series analysis, ARIMA Model and combination forecast model,Chongqing’s GDP during 2015—2020 is predicted and its comparative analysis is conducted. The research results show that the deviation of the three methods is small, however, the accuracy of combination forecast model is higher, and that Chongqing’s GDP yearly growth rate in the coming years will be maintained at about 10 percent.