Abstract: The tuna cooking liquor obtained by extracting protein and oil was used as the raw material to produce the seafood condiment base through yeast fermentation. Sensory evaluation and amino acid nitrogen of the reaction products were determined and odor changes were analyzed using electronic nose. Through single-factor experiments, the influence of yeast type, added amount of yeast, fermentation time, and salinity on fermentation degree and product was studied. The optimal fermentation process was further determined through response surface design. The results showed that the optimal conditions for fermentation of bonito cooking liquor were: Yeast 71B, yeast addition amount 4.5‰, fermentation time 6 h, salinity 0.26 mol/L. Under this condition, the sensory score of the fermentation broth was 9.31. The amino acid composition showed that after fermentation, umami amino acids (Asp, Glu), sweet amino acids (Gly, Ala) all increased, and bitter amino acids (Val, His) decreased significantly.