The invention discloses a vacuum microwave enzyme deactivating method, wherein the deactivation of enzyme is carried out on spread tea in a microwave heating manner under the condition of vacuum. Under the condition of vacuum, the microwave power is controlled for carrying out enzyme deactivating, the boiling point of water is reduced, and the evaporation rate of water vapor is increased, so that the enzyme deactivating time of tea is further shortened; and the enzyme deactivating temperature is reduced, so that the method is beneficial to reservation of nutrition substances such as amino acids, vitamin C, chlorophyll, aromatic matters and the like, and the quality of the tea subjected to enzyme deactivating is improved. According to the vacuum microwave enzyme deactivating method, the problems of inconsistent uniformity of enzyme deactivation, red peduncles and red leaves, burned edge, fire point, damage on the nutrition substances, more draining amount and reduction of the tea quality in the existing processes of tea withering, tea drying and tea steaming, high boiling point of water and slow evaporation rate of water in the tea is slow during the process of microwave enzyme deactivation under normal pressure, and serious damage on amino acids, vitamin C, chlorophyll and aromatic matters in the tea because of high water-removing temperature, and the like can be solved. The vacuum microwave water-removing method is simple and easy, and the water-removing tea quality is good.