The effects of drone-based foliar spraying of trace elements(zinc，iron and selenium，either alone or in a ternary mixture)on ear traits and concentrations of zinc，iron，selenium and other nutrients in the grains of fresh waxy maize were investigated to provide theoretical basis and technical support for the nutrient fortification and high-yield and high-efficiency production of fresh waxy maize. A field experiment was conducted using Zhenghuangnuo No. 2 as the plant material. A single element or ternary mixture of zinc，iron and selenium was sprayed on the leaf surface with a drone at the 12-leaf stage，the silking stage and the early filling stage of maize. Samples were collected at the early filling stage and the milk ripening harvest stage for determination of relevant parameters. The results showed that:(1)Compared with the control，foliar zinc spraying significantly increased the diameter，total dry weight and grain dry weight of the ear per plant by 3.8%，23.5% and 33.3%，respectively，at the early filling stage，and by 3.8%，7.5% and 7.7%，respectively，at the milk ripening harvest stage. The effect was more obvious at the early filling stage. Foliar spraying of iron，selenium or a ternary mixture of zinc，iron and selenium significantly increased the ear diameter，but had no significant effect on the ear total dry weight and grain dry weight per plant.(2)The drone-based foliar spraying could increase the concentration of iron，zinc or selenium in maize grains separately or simultaneously. Foliar spraying of a ternary mixture increased the grain concentrations of zinc at the milk ripening harvest stage of fresh waxy maize from 15.8 to 24.7 mg/kg with an increase of 56.3%，of iron from 18.0 to 24.2 mg/kg with increase of 34.4%，and of selenium from 14.9 to 417.8 μg/kg，which was greater than 150 μg/kg and met the selenium-rich requirement，simultaneous biofortification of these three micronutrients were achieved.(3)Foliar spraying of selenium alone significantly increased the grain iron concentration at the milk ripening harvest stage，and the grain selenium concentration after foliar spraying of a ternary cocktail was significantly lower than that of selenium alone at both sampling times，indicating synergistic or antagonistic effects among different elements. In conclusion，the drone-based foliar micronutrient fertilizer spraying technology could maintain and even increase the production of fresh waxy maize，and increase the grain concentration of iron，zinc or selenium alone or three together，achieving biofortification of one trace element or co-biofortification of three trace elements without yield penalty. It had a good application prospect for improving the micronutrient nutritional quality of fresh waxy maize grains and the micronutrient nutritional health status of animals/humans.