Abstract: A nebulizer comprises a housing, a closed pressure system, at least one pressure relief mechanism and a nebulization mechanism. The housing comprises a nozzle, and the nozzle comprises an outlet portion and an inlet portion communicated with a pressurized gas source. The closed pressure system comprises at least one gas inlet and a gas outlet. The at least one pressure relief mechanism is disposed on the at least one gas inlet. The nebulization mechanism is capable of moving to a nebulization position. An interior pressure in the closed pressure system is changed by the at least one pressure relief mechanism to control the nebulization mechanism for nebulization.