On basis of the back propagation artificial neural networks(BP ANN) method,and under consideration of the mean value differences caused by different sample collections for their individual differences and interdecadal variations,which may influence the simulation and prediction of summer rainfall patterns over eastern China,the cross validation and ensemble prediction ideas are adopted to improve the prediction method.An independent prediction is gotten during each cross validation test,and then many times cross validation test by the ANN model established based on different sample collections may give many times prediction results for the predicted year.Its performance seems good in the prediction test of four rainfall patterns over eastern China in summer.