Abstract: This paper adopts the nethos of fuzzy mathematics analysis to set up a new and more accurat aynthesis decision model on the basis of the synthetic judgment model with generalized fuzzy operation.the model has been used to predict the occurence of yellow rice borer in the first generation with the meteorological facts of wupin county.The result proves that the model is applicable.Examination wi th theinformation of the past twenty years shows the historical coincidences between the prognosis and the investigations were ninety-five percent.Comparing with the others, using the way can not only deal with the phenomenon of "fuzziness" in the fuzzy middle transition, but also fully apply the fact information and increase the accuracy,This paper clarifies the calculating method and discusses the details.