Based on the data of the Shaanxi Province’s constant price GDP from 1993 to 2010, the paper fitted, analyzed and pridicted the Shaanxi Province’s constant price GDP by the quadratic function, exponential function and ARIMA model .by comparation, the errors of three models are in turn 17.9483%， 8.7529%，3.3890e-06.The analyzed result indicated the ARIMA model is highly fitted the raw empirical data,error is almost zero,so combination forecasting model is not needed.