Objective To prepare antioxidant peptides from tilapia skin by microwave-assisted enzymatic hydrolysis and conduct structural analysis.Methods The processing conditions for preparing antioxidant peptides by microwave pretreatment-assisted alkaline protease hydrolysis are optimized through single-factor and response surface experiments, and the effects of microwave treatment on the structure of fish skin, the relative molecular weight, amino acid composition, and antioxidant activity of antioxidant peptides are analyzed.Results The optimal processing conditions for preparing antioxidant peptides by microwave-assisted enzymatic hydrolysis are as follows: microwave power of 441.50 W, microwave temperature of 61.00 ℃, microwave time of 20 min, hydrolysis time of 6.21 h, enzyme dosage of 2.20%, and solid-to-liquid ratio of 1:40 (g/mL). Under these conditions, the yield and antioxidant activity of the crude antioxidant peptides from tilapia skin are increased by 8.23% and 54.89% respectively, compared with the control group. Additionally, the hardness, gumminess, and chewiness of tilapia skin pretreated by microwave are significantly reduced compared to the control group, and the collagen fibers of tilapia skin are more dispersed and looser.Conclusion After microwave pretreatment, peptides whose relative molecular weight is below 1 000 can be obtained, with a high content of histidine, phenylalanine, tyrosine, and cysteine, and high antioxidant activity.