Significant variations in components of fresh milk with season, temperature, and milking time and frequency lead to large differences in yogurt quality. In this paper, the influence of the contents of milk protein, fat and lactose on water retention and acidity of yogurt during storage was studied. The results showed that the water-holding capacity of yoghourt stored at 4 ℃ was apparently enhanced with increasing addition of milk protein, fat and lactose contents. Moreover, the acidity of yogurt was increased significantly with increasing addition of milk protein content, but was not significantly affected by the amount of fat or lactose.