Small targets detection in optical imaging is a difficult problem in the field of computer vision.At the same time,with the expansion of imaging distance and the requirements of long range strikes and rapid attack/defense in modern warfare,there will be a lot of realistic needs for small targets detection.Therefore,how to quickly and accurately detect small targets in complex backgrounds is of great significance in areas such as intelligent control,visual navigation,and target monitoring.Reviews the research situation of infrared small targets detection,visible small targets detection and small targets detection based on deep learning in recent years at home and abroad,in order to seek new exploration and breakthrough,as well as provide useful reference for the development of small targets detection technology.