The fresh-cut apple slices were impregnated with different concentrations (1%, 2%, 3% and 4%) of organic acid including citric acid, ascorbic acid, malic acid and acetic acid. The color, yield, rehydration, deformation rate, texture characteris-tics and microscopic pore structure of freeze-dried apple chips were used as indicators to analyze the effect of different acid immersion on the quality of vacuum freeze-dried apple chips. The results showed that the △E value of freeze-dried apple slices treated with citric acid, ascorbic acid and malic acid increased with the increase of acid concentration, with relatively small △E value treated with acetic acid, and the color protection effect was good. The deformation rate of freeze-dried apple slices treated with citric acid, ascorbic acid and malic acid increased with increasing concentration, and was significantly higher than that in the acetic acid treated group and the non-impregnated group (P＜0.05), slight reduction in dipping group. The rehydration ratios of freeze-dried apple slices treated with acid impregnated were significantly higher than those in the non-dipping group (P＜0.05). At a concentration of 1%, the malic acid and acetic acid impregnation freeze-dried apple slices showed more completed tissue cells and thicker cell walls, which contributed to high hardness and small deformation rate. It was found that acetic acid could effectively improve the comprehensive quality of freeze-dried apple slices.