In recent years, object detection has become a hot topic in the field of information technology.Whether it is a research institute or a large-scale technology-based enterprise, it is pursuing the best object detection algorithm.RetinaNet is an important discovery.It can be seen that the Facebook AI team, the proponent of RetinaNet, has referenced a large number of object detection cases, making it a hot method in the field of object detection.It is better than YOLOv3 and is not so complex as Fastest R-CNN.In this paper, the application of RetinaNet in military vehicle detection is studied, and some suggestions are put forward for improvement.