Objective: In order to obtain the enzymatic hydrolysis solution of Spanish mackerel by-products with good taste and high peptide content. Methods: In this study, the influence parameters of the enzymatic hydrolysis process were optimized based on the orthogonal test. The effects of enzymolysis time, enzymolysis temperature, pH value, and enzyme dosage on peptide content and flavor dilution value (TD value) of enzymolysis solution were investigated. Results: The optimum enzymolysis conditions were as follows: enzymolysis time was 4 h, enzymolysis temperature was 35 ℃, enzymolysis pH was 8.0, and enzyme addition amount was 16000 U/g. At this time, the peptide content was 107.84 mg/mL and the TD value was 28.53. Conclusion: The peptide content and TD value in the verification test were higher than those in other experimental groups, indicating that the optimized enzymatic hydrolysis conditions were accurate. This study provided a theoretical study for the utilization of high value of Spanish by-products.