In the experiments of cabbage vacuum cooling with normal technique, the maximum temperature difference between the core and surface of cabbage is 12.3℃ because of its tight structure. According to analyzing results of the varieties of cabbage core and surface temperatures, gasification process of water and the way of heat exchange of cabbage during vacuum cooling process, a technique method was put forward to set the operation pressure range by automatic air compensating valve. By this means, it was found that the temperature difference between the core and surface of cabbage was decreased to 2.3℃. The results show that the selection of an appropriate range of automatic air compensating valve when some special foods are cooled in vacuum equipment can reduce the temperature difference in the foods.