The invention discloses a duct type large-diameter screw propeller, relates to the technical field of aircrafts, and solves the technical problem that an existing screw propeller is relatively low inmechanical efficiency and relatively high in operating noise. The duct type large-diameter screw propeller disclosed by the invention comprises a paddle wheel hub, an inner reinforcing ring and an outer reinforcing ring from inside to outside in sequence, wherein a plurality of connectors are arranged on the inner reinforcing ring in the circumferential direction at intervals; each connector is correspondingly connected to a main bearing truss girder respectively; one end of each main bearing truss girder is fixed on the paddle wheel hub, the middle section of each main bearing truss girder isfixed with the inner reinforcing ring, and the other end of each main bearing truss girder is fixed with the outer reinforcing ring. The duct type large-diameter screw propeller also comprises a plurality of paddles connected with the paddle wheel hub, the inner reinforcing ring and the outer reinforcing ring in an inclined manner in sequence, and the paddles are uniformly distributed around thecircumferential direction of the paddle wheel hub; the beginning end of each paddle is seamlessly connected with the paddle wheel hub, the middle section of each paddle is seamlessly connected with the inner reinforcing ring, and the tail end of each paddle is seamlessly connected with the outer reinforcing ring.