Abstract:We select 23 factors as restrict elements for the studies of occurrence and epidemic of wheat yellow dwarf from 1992 to 2009 in semi-arid climate area of northwestern China. Using the function of three-layer artificial neural network can approximate arbitrary continuous with arbitrary precision and simulated by nonlinear forecast system. We put a method of BP neural network model and set up the model through selecting 23 factors based on the data of 1992 to 2006. Prediction of 2007 to 2009 has been carried out. Results showed that the error ratio is between 0.001 and 0.034 when using incidence as the output results. Based on the predicted result indicating by disease grade, the output number of model is fully consistent with actual disease level, and the accuracy was 100%. The result also proved a feasible method of prediction wheat yellow dwarf use the BP neural network.