Deviation rectifying device for air knife of plastic film extruder

The utility model discloses an air knife deviation rectifying device of a plastic film extruder, which comprises an extruder head and air knives positioned on two sides of the extruder head, each air knife comprises an air outlet at the bottom, each air outlet comprises an upper air outlet and a lower air outlet, the lower air outlets are positioned below the upper air outlets of the air outlets, and the lower air outlets are close to two sides of a film. The air directions of the lower air outlets on the two sides are obliquely downward air directions facing the film, and smoothing structures are arranged at the bottoms of the lower air outlets on the two sides and comprise smoothing rollers. The air outlets in the upper portions of the air knives are formed in the two sides close to the position where a film is just extruded, so that when the film is just extruded, the film is rapidly cooled and solidified, the film is effectively prevented from deviating, and the air knives on the lower portion can effecti