Some characteristics of β-galactosidase enzyme that was isolated from a new born goat brain were studied. This study concluded that the enzyme is glucoenzyme in which the carbohydrate part constitutes 22.1% in accordance with phenol –sulfate acid method. The optimum pH for the enzyme activity is 5.5. The enzyme lost its activity completely at pH8.5, and showed great stability at the range of pH 4-6. The results indicated that the optimum temperature for the enzyme activity is 55Co at the optimum pH. The stability temperature for the enzyme is 35-60Co. The analytical results of 5%lactose solution hydrolyzed by the enzyme have indicated that the hydrolysis rate is between 40% after 60 minutes, to 95% after 270 minutes.