Objective To analyze the dynamic migration patterns of nutritional components in composite fruit vinegar during storage and thereby reveal the mechanism of storage conditions affecting the quality stability of the fermentation system.Methods Single-factor experiments combined with the surface methodology are adopted to optimize the fermentation parameters of apple-raspberry composite fruit vinegar, with the total acid mass concentration employed as the response value. Meanwhile, the composite fruit vinegar prepared by the optimized process is subjected to a 60-day storage test at ambient temperature in the dark.Results The optimal brewing parameters for apple-raspberry composite fruit vinegar are as follows: raspberry addition of 20 g/100 g, acetic acid bacterium inoculation of 10 mL/100 mL, and fermentation temperature of 32 ℃. The total content of the ten detected phenolic compounds in apple-raspberry composite fruit vinegar shows a trend of increasing with prolonged storage time.Conclusion Storage aging can effectively promote the accumulation of phenolic compounds in apple-raspberry composite fruit vinegar.