An atomizing assembly includes a housing, an atomizing base, an atomizing element, and a sealing member. The housing is provided with a liquid storage chamber and an airflow channel. The liquid storage chamber is configured to store liquid. The atomizing base is fixed to the housing and configured to seal the liquid storage chamber. The atomizing base is provided with a liquid inlet in communication with the liquid storage chamber. The atomizing element is disposed in the atomizing base and configured to atomize the liquid flowing into the atomizing element through the liquid inlet. The sealing member is movably disposed on the atomizing base and configured to seal or unseal the liquid inlet. An electronic atomizing device is further provided, which includes the aforementioned atomizing assembly and a power supply assembly connected to the housing and electrically coupled to the atomizing element.