The invention discloses a deflection mechanism of a lifting appliance. The deflection mechanism comprises a drive trolley, an arc-shaped arc rail and an arc gear rack corresponding to the arc rail. The drive trolley comprises a motor, a speed reducer, an axle, bearing pedestals and tooth-shaped rollers. The output end of the motor is connected with the speed reducer. The axle transversely penetrates an output hole of the speed reducer, an angle of 90 degrees is formed by the axle and an output shaft of the speed reducer, and the axle is driven by the speed reducer to rotate. The tooth-shaped rollers are fixed to the two ends of the axle. Each tooth-shaped roller comprises a tooth-shaped roller upper cylindrical face and a tooth-shaped roller upper gear, wherein the tooth-shaped roller upper cylindrical face is engaged with the arc rail, and the tooth-shaped roller upper gear is engaged with the arc gear rack. When used for mounting and demounting of fan blades by the fan blade lifting appliance in an high-altitude unmanned state, the deflection mechanism of the lifting appliance assists in adjusting the postures of the fan blades; the deflection mechanism is simple in overall structure and convenient to use; and compared with an existing deflection mechanism, the phenomenon that clamping appears due to the fact that the gravity center of a hanging object deflects is not prone to happening.