Ecological control methods are important for controlling agricultural pests. The Asian corn borer (ACB), Ostrinia furnacalis (Guenée), has been an extremely serious pest, that cause severe reduction in corn yields. The ubiquitous entomopathogenic fungus Beauveria bassiana has been used to suppress populations of the European corn borer (ECB), O. nubilalis, and ACB globally. Most studies have focused on the application of B. bassiana, with limited studies on the relationship between the fungus, corn, and insects. Our previous research indicated that B. bassiana with two mating-gene types, MAT1-1-1 and MAT1-2-1, could colonize corn. These mating-type genes had mutation sites cloned from endophytic fungal strains, which revealed corn plants and insects could impact fungal evolution. The purpose of the present study was to create endophytic symbiosis and determine the interaction among B. bassiana (entophytic fungus), corn plants, and ACB. We created a B. bassiana-corn endophytic symbiosis by inoculating two mating-gene type B. bassiana strains (MAT1-1-1 type B5 and MAT1-2-1 type B2) into corn plants in a suspension with a concentration of 1×10⁷ spores/mL. The effect of endophytic symbiosis on the growth of corn plants, oviposition preference of ACB adults, development of ACB larvae, and biological variation of B. bassiana were evaluated in the greenhouse. The results showed that endophytic B. bassiana could be detected from corn leaves in vitro by culture. ITS and mating-type gene amplification and sequencing confirmed the successful creation of endophytic symbiosis. The MAT1-2-1 type B2 treatment group showed a higher endophytic detection rate than MAT1-1-1 type B5, whereas MAT1-1-1 type B5 was more successful during co-inoculation than MAT1-2-1 type B2. The variation of the colony diameter and virulence of the recovered B. bassiana were not significant, but the sporulation quantity improved significantly, and the EN-B5 strain (recovered from the B5 treatment) changed the most obviously. The height of corn plants and dried biomass of treatment groups were higher than the CK group, while the underground root biomass significantly improved. The B5 strain contributed more to above-ground plant height and the B2 strain contributed more to underground root biomass. ACB moths were released into nylon-meshed cages. Egg quantity showed a significant difference in all treatment groups, which was lower than that in the CK group. Egg fecundity rate in the B2 group was 3.33%, but 53.33% in the CK group; therefore, the B2-corn endophytic symbiosis group was not the preferred host for ACB egg laying. The ACB larval survival rate and weight in treatment groups were significantly lower than those in the CK group. The ACB pupation rate of treatment groups was not significantly lower than that of the CK group, but there was a significant difference between B5 and B2 groups; the B5 group had the lowest survival (38.33%) and pupation rates (34.77%). These results demonstrated that the sporulation quantity of the recovered B. bassiana strains significantly improved, and the synergism of the two strains with different mating-type genes was shown. The two B. bassiana mating-types could colonize in corn plants and mutualistic endophytic symbiosis was formed, which reinforced corn growth and improved the resistance against pests. B. bassiana-corn endophytic symbiosis is important for the sustainable management of pests by inhibiting oviposition and suppressing larval and pupal development. The results also proved that mutualistic symbiosis could improve the ecological adaptability of B. bassiana and corn, which offered a new strategy for ACB control using endophytic symbiosis through the application of B. bassiana.