[Aim] Brontispa longissima and Opisina arenosella belong to the leafk-eating invasive pests of the Palmaceae, but they do not compete with each other when they eat plants at the same time. This article uses molecular biology methods to compare the intestinal flora composition and intestinal metabolic pathways of B. longissima and O. arenosella, in order to explore the correlation between the diets of them, and provide a basis for the comprehensive prevention and control of them.[Method] The 16S rRNA flora analysis and other prediction methods were used to analyze the intestinal microbial community and metabolic pathways of the two species.[Result] The results showed that the abundance of the Saccharibacteria community in B. longissima was significantly higher than that of O. arenosella. The abundance of Cyanobacteria, Actinobacteria, Acidobacteria, Verrucomicrobia, etc. in O. arenosella is significantly higher than that of B. longissima. The degree of intestinal metabolic pathways such as phosphonate and phosphinate metabolism, N-glycan synthesis in B. longissima is significantly stronger than that of O. arenosella, and the synthesis and degradation of ketone bodies, vitamin B6 metabolic pathways such as metabolism, riboflavin metabolism, flavonoids and flavonol biosynthesis in the intestine of O. arenosella are significantly stronger than those of B. longissima.[Conclusion] The relatively high abundance of Acidobacter spp. in O. arenosella may lead to its preference to eat old coconut leaves with high fiber content, but B. longissima is the opposite; At the same time, the significantly stronger metabolic strength of vitamin B6 in O. arenosella plays an important role in the construction of its spleen, and promotes the establishment of its ethnic group. The differences in bacterial abundance and the strength of metabolic pathways between the two species may affect their feeding habits.