Regarding the problem that when the area to be detected is large, the use of satellite or Unmanned Aerial Vehicle (UAV) alone will lead to the problems of low detection accuracy and slow detection speed respectively, a cooperative target detection method of “satellite-UAV” based on YOLO detection model is proposed.Firstly, the satellite equipped with YOLOv4-tiny model with channel pruning is used to quickly and preliminarily screen the target area in a large area.Secondly, the UAV equipped with YOLOv4 model with four-scale detection branches is mobilized to further accurately detect the areas containing the targets.The experimental analysis shows that the improved YOLOv4-tiny model can screen large-scale areas faster, and the improved YOLOv4 model has higher detection accuracy for the screened areas with targets.The cooperative detection of satellite and UAV can effectively combine the “fast” of the former with the “accurate” of the latter, and improve the detection efficiency.