The utility model discloses a branch pruning device based on an unmanned aerial vehicle platform. The device comprises a fixed bracket and a motor base fixed at the front end of the fixed bracket, a trimming motor is fixed on the motor base; a saw blade for trimming branches is mounted on an output shaft of the trimming motor; the motor base is further provided with an anti-reaction-force baffle parallel to the saw blade, the edge of the anti-reaction-force baffle is provided with a plurality of extending parts distributed in a radial mode, the projections of the roots of the extending parts on the plane where the saw blade is located fall into the periphery of the saw blade, and the projections of the outer ends of the extending parts on the plane where the saw blade is located fall out of the periphery of the saw blade. According to the unmanned aerial vehicle, the problems caused by a traditional manual method and a power-off felling operation mode are solved, the problem that an existing unmanned aerial vehicle for branch pruning is prone to unbalance during operation can be solved, the stability of the unmanned aerial vehicle during branch pruning can be guaranteed, and the pruning safety and reliability are guaranteed.