Abstract: In order to eliminate the fishy and bitter taste of mussel hydrolysate, the fermentation process of mussel (Mytilus edulis) hydrolysate were studied in this paper. Angel fruit wine yeast was used to ferment and the optimal fermentation technology was determined by optimizing the yeast addition, fermentation temperature and time according to sensory score and protein loss rate. The difference of flavor profile before and after fermentation was studied by sensory science combined with automatic amino acid analysis and mass spectrometry. The results showed when the fruit wine yeast was added at 0.2% and fermented at 35 ℃ for 2.0 h after treatment, the fishy, earthy and halal flavor of the hydrolysate decreased significantly, while the fermented and fruity flavor increased significantly (P<0.05). The content of sweet amino acid increased from 1.33 to 1.99 mg/g (P<0.05), the content of umami amino acid increased from 1.60 to 1.93 mg/g, the content of bitter amino acid decreased from 3.64 to 3.34 mg/g. A total of 32 volatile flavor compounds were detected in the mussel hydrolysate, which increased to 40 after fermentation, including aldehydes, alcohols, esters, acids, ketones and furans, 4-heptadienal, 2-octenal, nonanal and 1-octene-3-ol were the main odor sources in the mussel hydrolysate. After fermentation, nonanal, 2,4-heptadienal and 2-octenal were no longer used as flavor active components of mussel hydrolysates, and the OAV values of 1-octene-3-ol and octenal, which produced fishy odor, also decreased significantly, after fermentation, decanal, phenylacetaldehyde, 2-nonone and 2-undecanone were added as the flavor components of the mussel hydrolysate, which provided the floral and fruity aroma and fragrance for the mussel hydrolysate. Therefore, yeast fermentation could effectively improve the odor of mussel hydrolysate. This study would provide a theoretical basis for the elimination of odor in shellfish hydrolysate.