The background and technical difficulties of infrared small target detection are introduced. Three types of small infrared target detection algorithms are summarized, such as spatial-domain filtering, transform-domain filtering and time-domain filtering. The common target detection method and edge segmentation method of spatial-domain filtering and transform-domain filtering are analyzed through experiments. Experimental results show that three types of small infrared target detection algorithms have both advantages and disadvantages. Selecting specific target detection algorithm is more affected by the target and background feature. And the development trend of small infrared target detection is discussed briefly.