Focusing on the detection of infrared dim targets in space-based imaging systems, a multi-feature and spatio-temporal fusion algorithm is proposed. By analyzing characteristics of target and background in the image, firstly, an algorithm combining TOP-HAT and improved partial differentiation method is proposed for image preprocessing; Secondly, the local entropy feature and local gradient feature of the small target image are extracted from images to fuse, an improved interframe method is used for spatio-temporal fusion to enhance the target signal, then threshold segmentation is used to obtain the detection result. Theoretical analysis and experiments show that the algorithm proposed in this paper can not only suppress the background and enhance the target well; in addition, it is possible to realize the on-chip transplantation of hardware. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.