The present study aimed to illustrate the mechanism of grass carp’s myofibrillar protein absorbing fishy odor compounds by establishing the myofibrillar protein-fishy odor compounds（hexanal， heptanal， octanal and nonanal） system. The binding capacity and molecular interactions of fishy odor compounds to myofibrillar protein were analyzed by HS-GC-MS， and the changes of thermal stability and secondary structure of myofibrillar protein were detected by DSC， UV spectra， fluorescence spectroscopy and Raman spectroscopy. Results indicated that the binding capacity of linear-chain aldehydes to myofibrillar protein increased with the chain length of the aldehydes. Moreover， the presence of these flavour compounds caused the protein structure unfolding， resulting a transition from α-helix into β-sheets and β-turns， and reduced the fluorescence intensity and thermal stability of the protein. Molecular interactions between aldehyde compounds with myofibrillar protein of grass carp were mainly hydrophobic interactions， and partly of them were hydrogen bonds or ionic bonds.