The invention discloses a map merging method of unmanned aerial vehicle visual SLAM under city complex environment. The method comprises the steps of 1, collecting an image through an RGB-D camera installed on each unmanned aerial vehicle, utilizing the unmanned aerial vehicle to conduct pretreatment on the image, and then conducting
image registration; 2, constructing a visual
odometer, and achieving loop detection; 3, optimizing the posture of the unmanned aerial vehicle; 4, constructing an octomap map, and achieving real-time on-line SLAM; 5, transmitting the octomap into a ground computer, merging a local octomap into a global octomap, and then transmitting the merged all-region octomap to the unmanned aerial vehicle. According to the map merging method of the unmanned aerial vehicle visual SLAM under the city complex environment, calculated quantity is reduced, real-time on-line SLAM can be achieved, and hidden danger of information losses brought by unstable
wireless transmission is reduced; meanwhile, the task
execution time is shortened, the task execution efficiency is improved, hidden danger brought by insufficient unmanned aerial vehicle cruising ability, finally more precise positioning can be obtained, and a more precise map can be established.