Abstract: In order to investigate the mechanism by which high pressure processing (HPP) treatment enhances the tenderness of marinated duck drumsticks, In this study, we analyzed the pattern of structural changes of myofibrillar proteins during high pressure processing (400 MPa, 15 min) by determining the surface hydrophobicity, sulfhydryl content, chemical force, secondary structure and microstructure. The results revealed that the hydrophobicity of myofibrillar proteins initially increased and then decreased, reaching a maximum of 51.03 after 12 minutes of treatment. The total thiol content decreased by 40.6% after 15 minutes of treatment, while the free thiol content increased by 42.7%, and disulfide bonds significantly increased by 189.2%. Tryptophan and tyrosine residues were exposed, indicating changes in protein tertiary structure. After 15 min of HPP treatment, the α-helix content of myofibrillar protein decreased from 20.63% to 13.45%, and the content of irregular coils increased from 23.93% to 28.67%, suggesting rearrangement of the protein secondary structure. SDS-PAGE electrophoresis and scanning electron microscopy results demonstrated protein depolymerization, significant reduction in particle size, and more uniform distribution. In conclusion, during high-pressure processing, significant changes occur in the tertiary structure, secondary structure, and microstructure of duck leg myofibrillar proteins, contributing to the improvement of duck meat tenderness. This study provides a theoretical basis for the application of high-pressure technology in improving meat tenderness and provides insight into the underlying mechanisms.