Abstract: This study utilized duck legs as experimental materials to analyze the effects of vacuum low-temperature braising on the protein structure of duck legs. The research methods included tissue structure observation, myofibrillar protein extraction, microstructure determination, protein solubility measurement, and myofibrillar fragmentation index (MFI) determination. The results showed that the cross-sectional structure of unbraised duck legs was tightly packed and uniform in clumps. After being braised for 2 h, the cells shrank, the fiber gaps widened, sarcomeres displayed wavy deformations, and the M-lines loosened and disappeared. During the 0~2 h of braising period, the hydrophobic characteristics of myofibrillar protein significantly increased (P<0.05), the maximum emission wavelength (λ_max) of intrinsic fluorescence red-shifted to 351 nm, protein solubility decreased significantly by 62.09% (P<0.05), and MFI increased significantly (P<0.05), indicating enhanced protein thermal denaturation and increased meat hardness. From 2 to 8 h of braising, protein solubility first increased significantly(P<0.05) and then remained stable, while MFI showed no significant changes (P>0.05). The λ_max of intrinsic fluorescence blue-shifted from 351 nm to 349 nm, and the maximum fluorescence intensity (FT_max) increased by 3.56%. Meanwhile, larger molecular weight parasmyosin gradually degraded. In the secondary structure, the proportion of β-fold initially increased and then decreased, whereas the β-turn proportion initially decreased and then increased, suggesting that protein denaturation decreased in the later stage, the structure became more compact, and tenderness improved. In conclusion, vacuum low-temperature braising technology can significantly improve the tenderness and texture of duck legs. This study provides scientific evidence for the application of vacuum low-temperature braising technology in duck legs processing.