To effectively control weeds in soybean-maize strip intercropping field, closed herbicide application of 960 g/L S-metolachlor emulsifiable concentrate(EC) was conducted using a plant protection unmanned aerial vehicle(UAV). The experiment included five treatments: three UAV application rates(1 800, 2 250, and 2 700 g/hm2), one knapsack sprayer application treatment at 2 250 g/hm2, and a water spray as the control. The results showed that at the formulation dosage of 2 700 g/hm2, the application of 960 g/L S-metolachlor EC via UAV achieved the optimal weed control efficacy, with plant density reduction and fresh weight reduction rates of 85.32% and 88.45%, respectively. This treatment effectively controlled both monocotyledonous and dicotyledonous weeds in the soybean-maize strip intercropping field. Compared to the control group, the herbicide treatment significantly increased crop yields: soybean yield increased by 10.09%-17.18%, and maize yield increased by 13.90%-18.12%. In conclusion, the UAV-based application of 960 g/L S-metolachlor EC can be recommended for widespread adoption in soybean-maize strip intercropping fields.