This study reveals the physicochemical, microbial, flavor, and sensory changes in sauced duck from the marinating phase to the end of storage, divided into six stages (stages A–F). The changes in color, total plate count, total volatile basic nitrogen, and thiobarbituric acid reactive substance at different stages were clarified. We utilized 16S rRNA gene sequencing, GC-IMS, and GC-MS to explore the changes in bacterial flora, fatty acid composition, and flavor characteristics. The dominant bacteria identified in stages A–C included Psychrobacter, Flavobacterium, and Pseudomonas, while Lactobacillus and Staphylococcus dominated during stages D–F. Aldehydes, esters, alcohols, and ketones emerged as the main flavor compounds. Several unsaturated fatty acids significantly (p < 0.05) decreased from stage A to stage F. The sensory quality of sauced duck improved. The potential reactions were determined, and correlation analysis of sauced duck samples across different stages was performed. 3-Methy-1-butanol could be a crucial indicator of sauced duck’s overall quality. This research could support the treatment optimization of sauced duck products
