A method of small target detection is presented in IR images which combining local probability and edge information of the image.At first,this method figures out the sum square of each pixel′s probability in image windows to judge whether the window is an object area using threshold.Then,computes the edge information of the central pixels in every object area to eliminate strong edge noises and detect small target.Experimental result shows the method is not only simple,efficient and good at detecting small target in complex background,but also largely decreases the computation of the followed multi-frame process.