The invention discloses a rudder propeller, and belongs to the field of marine machinery. The rudder propeller comprises a supporting seat and a swinging mechanism, wherein the supporting seat comprises a supporting bottom plate, a supporting side plate and a supporting cover plate; a calibration object is arranged at one end close to the supporting cover plate, of the swinging mechanism; a calibration hole is formed in the supporting cover plate; a device for calibration is arranged in the calibration hole; and the calibration device is in tight connection with the supporting cover plate, and is used for detecting whether the calibration device is over against the calibration object or not. According to the rudder propeller disclosed by the invention, the calibration hole is formed in the supporting plate of the supporting seat, the calibration device is arranged in the calibration hole, and the calibration object is arranged on the swinging mechanism; and the calibration object is mounted before the supporting cover plate is mounted, so that the calibration object can be arranged at an appropriate position of the swinging mechanism, and the situation that when the calibration object is over against the calibration device, an autorotation axis of a propeller is parallel to the length direction of a hull, and the propeller faces the rear part of the hull is guaranteed; and the problems that the error is large and the accuracy is low due to manual range estimation are solved.