Cow leather without sulfide residues and low-temperature enzyme unhairing preparation process thereof

The invention provides a low-temperature enzyme unhairing method for preparing cow leather. The method comprises the following steps: (1) cleaning: cleaning fresh cow leather, removing the dirts attached on the surface of the leather and needless subcutaneous tissues; (2) performing enzyme unhairing: adding a conventional enzyme for unhairing in water at 15-28 DEG C, adjusting the pH value to 7.5-11 to unhair; (3) unhairing: removing the loose hairs on the leather; performing alkali steeping and dealkalization: steeping the leather in a sodium hydroxide solution, introducing CO2 gas at the room temperature to dealkalize and ensure that the the pH value at the end point is 7.5-8.5; and (5) tanning to obtain the finished cow leather. The prepared leather hardly contains sulfide residues.