An airbag device is disclosed. The airbag device is applied to the field of preventing foreign material in the pipelines and is based on composite structure. In comparison to the normal filter situations, filter units in vertical pipelines should not only bear a certain rate of water flow but also hold the dropped parts from the aloft place. For example, the condensate water from the nuclear power plant may comprise some small parts. With the high-speed development of nuclear power, to speed up the development of the water filter in this area, the airbag device in this paper provides a simple but effective method to meet the filtration needs.