The invention relates to a handpiece body of a three-layer coextrusion film blowing unit. The handpiece body of the three-layer coextrusion film blowing unit comprises a spiral body, an inner die head, a middle die head, an outer die head, a mouth die and a pressing plate, wherein the spiral body, the inner die head, the middle head, the outer die head, the mouth die and the pressing plate are orderly distributed from left to right along the length direction, the spiral body is arranged in the middle of the handpiece body, and comprises two parts which are a vertical portion and an extension portion, the lower portion of the extension portion outwardly extends, a first spiral slot is arranged on the outer wall of the vertical portion, an axial connecting hole is inwardly arranged on the lower end of the vertical portion of the spiral body, and a first feeding channel is inwardly arranged on the top end of the axial connecting hole in the axial direction. The handpiece body of the three-layer coextrusion film blowing unit can achieve to process composite packing films such as low-density polyethylene (LDPE), high-density polyethylene (HDPE), linear low density polyethylene (LLDPE), ethylene vinyl acetate (EVA) and the like, is beneficial for high speed composite, uses multiple colors to print, and is excellent in composite effect, high in product quality, convenient in maintenance and repair and long in service life.