In order to satisfy the design objective of a certain vertical takeoff and landing UAV,the ducted variable pitch propeller is designed for satisfying vertical takeoff and landing and fixed wing forward flight.Based on the blade element-momentum theory and ducted propeller vortex theory,a preliminary result has been calculated through the program iteration and coupled CFD method.The final propeller design result therefore can concluded by returning this data into the corrected ducted thrust factor so as to establish a corresponding 3D model,of which the rationality of the design has been verified through ground tests.Test results shows that the designed ducted variable pitch propeller can meet the expected design objective within the test scope.