A closed nebulizing system for removing bubbles includes a first pump, a nebulizing module and a second pump. The first pump is for providing a fluid. The nebulizing module includes an outlet channel, an inlet channel connected with the first pump, and a plurality of nozzles for nebulizing and ejecting part of the fluid. The second pump is connected with the outlet channel for outputting non-nebulized fluid. The first pump, the nebulizing module and the second pump form a closed fluid loop, so that the fluid continuously contacts with the plurality of nozzles and bubbles generated during nebulization process are evacuated from the nebulizing module.