The utility model relates to a ventilation unit is used to maize inn, it includes the connecting frame, its characteristics are: still include the ventilation pipe, the one end of ventilation pipe is the socket end for the end of pegging graft, the other end, and the grafting end of ventilation pipe is along splitting into a plurality of segmental arc week, and at least one segmental arc mouth limit sets up the outside couple of hook end, the outside hole enlargement of socket end of ventilation pipe, set up and get in touch the groove that corresponds, the grafting of ventilation pipe hold the dress in the through -hole, articulate on the connecting frame. At ordinary times, pull down the ventilation pipe in order reducing the space, during the use, earlier to the partial maize of packing into in maize inn, place ventilation unit in maize inn again in the middle of, select the orientation of ventilation pipe, press segmental arc that the ventilation pipe linked firmly the couple, wear the dress with it and in the connecting frame, to the through -hole of not connecting the ventilation pipe, move pin to through -hole department, prevent that the maize from getting into the connecting frame in, continue to the maize of packing into in maize inn.