Abstract: In order to determine the control effect of mesotrione·nicosulfuron·terbuthylazine 31% OD on weeds in maize field, the best field dosage and the safety of corn, this study used post seedling stem and leaf spray treatment and regular investigation to conduct field efficacy tests. The results showed that at a dosage of 418.5-465.0 g·ha^-1, the mesotrione·nicosulfuron·terbuthylazine 31% OD had the highest plant control effects on Polygonum bungeanum, Amaranthus retroflexus, and Echinochloa crusgalli after 15 days of application, reaching 95.27%, 93.65%, and 97.06% respectively. After 30 days of application, the control effects on weed fresh weight were 96.91%, 96.02%, and 97.98%, all significantly better than the control agent. The amount of corresponding active ingredients was less than that of the control agent, and there was no significant harm to maize, compared to manual weeding treatment, the yield increase rate was from-6.03% to-1.93%. Considering the comprehensive cost and effectiveness of medication, the recommended dosage was 418.5-465.0 g·ha^-1. The mesotrione·nicosulfuron·terbuthylazine 31% OD can effectively control weeds in corn fields and has good safety for maize.