Abstract: Qualitative and quantitative analysis of flavonoids of Citrus reticulata cv. Chachiensis peel dried under natural sun drying and different hot- air drying conditions were determined by HPLC, and the compositions of its essential oils were detected by GC- MS. The results showed significant difference in the contents of four main flavonoids of Citrus Chachiensis peel under different drying temperature such as 36, 40, 45, 50℃ compared to natural sun drying, whereas no significant difference was found under 42℃ hot- air drying.Total ion chromatograms of essential oils were basically the same, though the total contents of essential oils of Citrus Chachiensis peel by hot- air drying were significantly higher than natural sun drying, and some differences in the types, numbers and relative contents of the composition of essential oils. The essential oils of Chachiensis peel under 42℃ hot- air drying was closest to natural drying. Conclusion: Considering saving energy and improving production efficiency, 42℃ hot- air drying is a relatively good drying method to preserve flavonoids and essential oils of Citrus Chachiensis peel.