This study investigated glycosylated casein in whole milk powder and explored its enzymatic property. The casein extraction weight percentage were determined by different pH, different acids, and different methods. The casein was analyzed by SDS-PAGE electrophoresis, and the glycosylated casein were identified via the method of periodate-schiff alkali dyeing and the experiment of morse. The casein was hydrolyzed by papain and the amino acid content was determined accordingly. Results: The percentage of casein extracted under pH 4.6 was significantly higher than that of other groups (P<0.05). The weight percentage of casein extracted from acetic acid (pH 3.58) was (4045±0.66)%, which was significantly higher than that of other groups (P<0.05). The percentage (46.13±0.46)% of casein extracted by tannic acid was significantly higher than that of other methods (P<0.05). The results of casein SDS-PAGE electrophoresis both showed the same 3 bands either different acids or different methods on casein extraction, and their molecular weights were 34, 24, and 60 ku, respectively, and the 34 and 24 ku were glycosylated casein by the method of periodate-schiff alkali dyeing. The results of morse experiment showed that milk powder casein exist glycosylated casein. The content of free amino acid from whole milk powder was significantly higher than that from fresh milk after papain hydrolysis (P<0.05). Whole milk powder has glycosylated casein, their molecular weights are 34 and 24 ku respectively, which are easy to hydrolysis.