The future 5-year precipitation forecasting was made for Horchin sandy land by using Mean Generating Function-Optimal SubsetRegression (MGF-OSR) based on the reconstructed series of 181years. The years that the absolute values of relative errors less than of 3%,5%, and 10% respectively account for 36.46%, 64.64%, 93.37% of the modeling years, and the simulation accuracy is higher in modeling pe -riod. The simulated values are consistent with observed data in the experiment period from 2007 to 2010, during which the absolute values ofthe relative errors are 11.40%, 6.73%, 22.06% and 5.49%, respectively. By forecasting, 2011, 2012, 2014 and 2015 are normal years for pre -cipitation, and 2013 is a dry year for precipitation.