In this paper,a bio-inspired path planning algorithm in 3D space is proposed.The algo-rithm imitates the basic mechanisms of plant growth,including phototropism,negative geotropism and branching.The algorithm proposed in this paper solves the dynamic obstacle avoidance path planning problem of Unmanned Aerial Vehicle (UAV) in the case of unknown environment maps.Compared with other path planning algorithms,the algorithm has the advantages of fast path plan-ning speed and fewer route points,and can achieve the effect of low delay real-time path planning.The feasibility of the algorithm is verified in the Gazebo simulator based on the Robot Operating System (ROS) platform.Finally,an actual UAV autonomous obstacle avoidance path planning experimental platform is built,and a UAV obstacle avoidance path planning flight test is carried out based on this actual environment.