Abstract: This study evaluated the effects of cinnamon extract immersion treatment on the quality improvement of prefabricated small yellow croaker during refrigeration. The changes in total volatile base nitrogen (TVB-N) content, total viable count (TVC), K value, sensory evaluation, pH, texture, color, thiobarbituric acid (TBA) content, total sulfhydryl content, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and muscle tissue microstructure of prefabricated small yellow croaker treated with cinnamon extract immersion group (CE) and distilled water immersion group (CK) during storage at 4 ℃ for 14 days were investigated. Results revealed that, the TVB-N content of the CK group reached 31.85 mg/100 g at day 12, which exceeded the limit requirement for qualified products, while the CE group did not exceed 30 mg/100 g at day 14. At the 10th d, the TVC and K values of the CK group were 7.65 lg CFU/g and 59.82%, respectively, which exceeded the qualified aquatic product limit (7.00 lg CFU/g). At this time, the TVC and K values of the CE group were 6.42 lg CFU/g and 40.65%, respectively, which were still in compliance with the qualified aquatic product limit, and effectively delayed the increase in TVC and K values. At the 14 d, the TBA content and pH values of the CE group were lower than those of the CK group, and sensory score, total sulfhydryl content, hardness, adhesiveness, and chewiness were better than those of the CK group. However, it did not significantly affect its elasticity and gumminess (P>0.05), while maintaining the integrity of the muscle tissue structure. Consequently, cinnamon extract immersion treatment improved the freshness, texture, sensory properties, lipid oxidation, as well as protein oxidation and degradation of prefabricated small yellow croaker during refrigeration, thereby retarding the deterioration of quality. This research provides technical and data support for quality regulation, safety assurance, and shelf-life extension of prefabricated small yellow croaker.