The invention relates to a suspension hot-air enzyme-deactivating method for tea, belonging to the technical field of agricultural machines. The method employs a suspension hot-air enzyme-deactivating machine and comprises the following steps: step 1, starting a centrifugal fan to deliver high-temperature hot-air with a predetermined temperature provided by a heat source to an enzyme-deactivating chamber through an air supply pipeline; step 2, inputting green tea leaves from a feeding inlet and allowing the green tea leaves to enter the enzyme-deactivating chamber along with the high-temperature hot-air; step 3, regulating and controlling the velocity of the hot air by using a hot-air velocity regulating device, observing the green tea leaves in the enzyme-deactivating chamber and allowing the green tea leaves to be in a suspension state; and step 4, allowing the green tea leaves to automatically flow into a cooling and moisture-regaining chamber as the specific gravity of the green tea leaves gradually decreases with water content, carrying out moisture elimination and cooling, then allowing the tea leaves to fall and to be output, and receiving the tea leaves falling down from a blanking opening by using a collecting box. With the method provided by the invention, the tea leaves are uniformly heated during enzyme deactivation, fragmentation of the tea leaves is effectively prevented, and tea quality is guaranteed; and the method is suitable for mass production.