The glycosylation of casein and whey protein in milk powder and its enzymatic hydrolysis property were studied. The casein and whey protein in milk powder were extracted by different methods. The compositions of casein and whey protein were analyzed by SDS-PAGE electrophoresis, and glycosylated casein and whey protein were identified by periodate-schiff alkali dyeing and Morse experiment. Amino acid content was determined after papain hydrolysis of casein and whey protein in milk powder and fresh milk. The results showed that the percentage of casein extracted by tannic acid was 46.13%, which was significantly higher than that of other groups (p<0.05). The method of lactic acid fermentation was the most efficient method to extract whey protein. The results of SDS-PAGE showed that the molecular weights of the casein and whey protein were 24, 34, and 60 ku, and 14 and 18 ku, respectively. The casein of 24 and 34 ku, and the whey protein of 14 ku were both glycoproteins by periodate-schiff alkali dyeing. The results of Morse experiment of casein and whey protein showed that milk powder exist glycoprotein. The results of milk protein hydrolysis by papain showed that the content of free amino acid in casein dehydrated from milk powder was significantly lower than that from fresh milk (p<0.05), and the same results to that of whey protein. Milk powder contained glycosylated casein, they were 24 and 34 ku of casein and 14 ku whey protein. The degree of milk protein hydrolysis from milk powder is lower than that from fresh milk.