Abstract: The purpose of this paper is to analyze the effect of one spray and three prevention on agronomic traits such as stress resistance and 100-grain weight of summer maize in the middle and late stage of Huang - Huai - Hai region. In this study, ''Zhengdan 958'' was used as the research object to select the best spraying time through variance analysis. The results showed that all treatments had significant effects on agronomic traits of summer maize (p < 0.05). Analysis of field traits: T4, T5, T6 treatment reached significant level compared with T7, All the traits of T1, T2, T3 treatment improved, T5 treatment was the best and T7 treatment was the worst. In the analysis of indoor seed testing, the differences among other traits except grain water content reached significant levels. The analysis results of seed yield, 100 - grain weight and yield traits were similar and T5 was significantly superior to T7. The grain number per spike, grain protein content and mildew rate traits T7 and T5 all reached significant levels. Spraying the mixture of bactericide、pesticide and some micro-fertilizer after summer maize pollen dispersal can significantly improve agronomic traits and prolong the filling duration, which can provide theoretical basis for general corn cultivation and improvement of corn yield and quality.