Dye-free coloration of wool fabric was performed by using the Maillard reaction between reducing sugars and wool keratin. SDS-PAGE gel electrophoresis, spectrophotometry, DNS method and K/S value of the colored wool fabric were used to investigate the reaction between sugars and keratin, the effect of reducing sugar type and reaction conditions on the coloring property of wool fabric. The results showed that new glycoproteins with higher molecular weight were formed from the reaction between reducing sugar and wool keratin and the absorbance value at 540nm of the reaction solution changed obviously, which indicated that colorants were produced via the Maillard reaction between sugars and keratin. A stronger color yield of the colored fabric was obtained with xylose than that of galactose and glucose. The appropriate conditions for wool coloring were at 90℃ and pH=9. The colored yield of increased 23.0% after H2O2 pretreatment of wool fabric. The color fastness to washing and brushing and dry/wet rubbing fastness of the colored fabric via Maillard reaction were excellent with 4-5, 5, 5, 5 degree, respectively, but the color fastness to light is only 2 degree.