The present invention discloses that a plasma aerosol device includes a gas tunnel, a dielectric barrier discharge module, and a liquid tunnel. The invention uses a mechanism similar to a dielectric barrier discharge (DBD) electrode system, thus to enable generating a plasma active water mist which riches in free radicals such as reactive nitrogen species (RNS) and reactive oxygen species (ROS). Therefore, this invention is able to be used in medical, sterilization, agriculture and preservation industries.