Abstract In this study, a carvacrol-allicin-anthocyanin composite film was fabricated for the preservation of postharvest blueberries and the application of freshness monitoring. In order to explore the effect of the composite film on the storage quality of postharvest blueberry fruits, 18 quality and physiological indexes of postharvest blueberry fruits were analyzed. The effect of the composite film on the freshness monitoring of blueberry fruit was investigated, and the color difference of the composite film was analyzed. The results indicated that the changes in nutrients and other indicators of blueberries during storage demonstrated that their preservation quality was maintained.. In addition, it results in significant discoloration of three different packages of blueberry fruits commonly found on the market during storage. This study provides a theoretical basis for the postharvest preservation of blueberry fruits, and alsoprovides technical parameters for monitoring blueberry fruit freshness.