Aiming at infrared images with background interference and low SNR, an infrared moving target detection method based on frame difference and adaptive threshold region growing was proposed. Firstly, the top-hat transform was adapted on the input infrared images in order to inhibit the large area of background interference. The algorithm used the method of frame difference to extract target regions initially between the adjacency images. Secondly, it analyzed the characteristics of infrared targets, and proposed an adaptive threshold segmentation algorithm based on image gradations. Finally, using the target centroid as the seed points and the adaptive threshold as the segmentation criteria, the region growing was applied on the pretreated images, and the infrared moving target detection was achieved. The results show that the algorithm in this paper can inhibit the large area of background interference and achieve the complete extraction and detection for one or more infrared moving targets.