The utility model belongs to the technical field of the aircraft feather, a variable pitch mechanism is disclosed. Variable pitch mechanism installs at rotatable oar epaxially, and the upper end of oar axle is provided with the propeller hub, and the circumference of propeller hub is provided with a plurality of oar clamping dead axles, is provided with the oar that is used for fixed paddle through the bearing on every oar clamping dead axle and presss from both sides, variable pitch mechanism establishes the rotation that can keep apart the oar axle at the oar off -axial including the cover, just can follow the isolation unit of oar axle up -and -down motion, keeps apart the unit and contains the rotation inner circle and do not rotate the outer lane, circling in the rotation and evenly being provided with axle lateral parts that a plurality of and oar pressed from both sides and corresponding the oar of being connected and press from both sides the pull rod, the oar presss from both sides the pull rod and is the rotation with the lateral part that rotates inner circle, oar clamp to be connected, it is provided with the driving isolation unit drive unit of motion down on the whole on the outer lane not rotate. This variable pitch mechanism has solved the oil that exists and has moved rotor flight control system and require enough fast problems of driving system response speed among the prior art, and the device simple structure, convenient to use.