Abstract: Serum vitamin A value in 163 cases of various dermatoses and 100 healthy subjects in Xian region were determined by fluorescent spectrometry. The mean serum vitamin A.value of the healthy control group was 97.74±22.52 μg/dL;and those of:erythrokeratoderma progressiva symmtrica, pityriasis iubra pilaris, lichen planus, melanosis, vitiligo and avitaminosis A were in normal ranges; but those of acne, seborrhoic dermatitis, pemphigus vulgaris and psoriasis were under the normal ranges (P<0.05~0.01).Finally, the rational use and the mechanism of vitamin A in these dermatoses are also discussed.