Abstract: The Spodoptera frugiperda is a pest that moved to China in 2019, causing different degrees of economic losses. In Nanjian, it is mainly harmful to the leaves and young stems of maize, causing incomplete leaves and affecting the yield of maize. 100 representative maize plants were selected for plant system investigation and analysis. The results showed that leaf integrity had significant or extremely significant linear regression relationship with 5 factors, such as yield per plant, row number per ear, 100 grain quality, plant height, stem base diameter, but no significant correlation with ear height. In particular, there is a regression equation of y =-68.09 + 267.27 x between leaf integrity and yield per plant, and there is a standard error of 10.55 g.