Aiming at problem that most research on obstacle avoidance of multi-rotor unmanned aerial vehicle（UAV） using artificial potential field（ APF） method

only consider the safe arrival to the target point

rarely considering the actual need of flying on planned path

by giving planned path a"line potential field "in APF algorithm

the obstacle avoidance and planned-path flying are combined

so that the UAV is able to return to the planned path after avoiding obstacle. Considering the UAV has a wide movement range

the Attractive Potential Field in traditional APF method does not apply well to the UAV

so the Attractive Potential Field is improved. It is also found that the introduction of"Line Potential Field"can easily lead UAV fall into the local optimum. After analyzing on this problem

this problem is solved by improving the repulsive potential field（ RPF）. Simulation verify the effect iveness of aboved impoved improvement.