Maillard reaction products of cod peptides, D-xylose, and dihydromyricetin (DMY) were prepared. The effects of DMY on the flavor profile of the reaction products under different pH conditions were investigated using UV-vis spectroscopy, fluorescence spectroscopy, free amino acid analysis, GC-MS, and electronic nose detection. Higher pH promoted the Maillard reaction. The addition of DMY reduced, to some extent, the formation of volatile furan and pyrazine compounds in the reaction system, while promoting the formation of fresh volatiles such as 1-dodecene, D-limonene, and isoborneol. Furthermore, under the influence of DMY, the total free amino acid content in the D-xylose/cod peptide reaction system decreased, and the proportion of flavor amino acids changed. At pH 9, the total free amino acid content in the system reached its minimum of 55.95 mg/L, and the proportions of bitter, umami, and sweet amino acids were 4.01%, 14.84%, and 46.44%, respectively. Hence, the proportion of bitter amino acids was the lowest, whereas the proportion of umami amino acids was the highest. The flavor base exhibits a fresh plantlike aroma, relatively lower bitterness, strong umami taste, and good flavor balance. In general, the addition of DMY can effectively mask the fishy smell of the flavor base. This finding provides guidance for developing flavor base materials that reduce bitterness and increase freshness.