Performing missions in complex environments has become an inevitable trend in the development of rotorcraft UAVs.In order to enable the rotorcraft UAVs to efficiently and safely execute missions in complex environments, scholars have conducted extensive research on binocular-vision obstacle avoidance technology for rotorcraft UAVs.In order to understand current situation and development trends of binocular-vision autonomous obstacle avoidance technology for rotorcraft UAVs, the composition of the binocular-vision obstacle avoidance system is introduced, and the role each technology plays in the binocular-vision obstacle avoidance system is analyzed at first.Then, the camera calibration methods, stereo matching algorithms and obstacle avoidance algorithms commonly used in binocular-vision obstacle avoidance technology are introduced, the advantages and disadvantages of each are summarized, and the latest research progress is expounded.Finally, the development directions of binocular-vision obstacle avoidance technology are predicted.