A novel extraction algorithm for infrared moving target is proposed based on spatio-temporal information. The proposed algorithm efficiently utilizes the target intensity feature,surrounding background and the moving information. In time domain segmentation,Gauss distribution model of frame difference background is established to determine the infrared target region via change detection mask. The spatial relation matrix between pixel and region is constructed to constrain the classical fuzzy C-Means clustering (FCM). And then,the region which contains the entire target is segmented efficiently based on the improved fuzzy clustering algorithm. At last,infrared target extraction is achieved by the fusion of spatio-temporal results. Experimental results verify the effectiveness and robustness of this extraction algorithm which can extract the infrared target correctly.