According to the problem of low detection rate for single frame image during the small moving in. frared target detection process, on the basis of analyzing the characteristics of infrared images of small moving tar. gets, a method for detecting small infrared targets based on sequence image grouped decision is put forward. Image difference method is used to extract target information. Edges of images are expanded and centroid of connected do. mains is chosen to construct sliding neighborhood blocks. Decisions of target positions are made by making full use of continuity of target tracks and random distribution characteristics of noise finally. The experiments prove that the detection method of sequence image has a higher detection rate than that of single frame image detection method.