Abstract: Taking eggplant as test materials, the effects of spraying exogenous nitrogen and melatonin on morphological development, chlorophyll content, photosynthetic efficiency, antioxidant enzyme activity and osmoregulator of eggplant seedlings under waterlogging stress were studied by pot experiment, in order to clarify the regulatory effects of exogenous substances on eggplant response to waterlogging stress.The results showed that the damage caused by waterlogging could be effectively alleviated by spraying exogenous nitrogen and melatonin in seedling stage.The combined application of nitrogen and melatonin could significantly improve the morphological development of seedlings, the activities of antioxidant enzymes, the contents of soluble sugar, soluble protein and proline in leaves, and enhance the photosynthesis of leaves, which was better than that of single spray treatment.In conclusion, spraying exogenous nitrogen and melatonin could enhance the photosynthesis of crops, improve the activity of antioxidant enzymes, reduce chlorophyll degradation and membrane lipid peroxidation, alleviate the damage of waterlogging stress of eggplant, so as to enhance the waterlogging resistance of eggplant.