Because of the low signal-to-noise ratio,the detection rate and real-time performance of infrared small dim targets are influenced seriously.In this paper,a new small dim infrared target detection m ethod is proposed to solve the problem presented above.The background of an infrared image is process ed by multi-scale Laplacian of Gaussian (LoG) algorithm,which can highlight infrared targets and t he edge of background.The LoG operator with anisotropy is proposed,which is sens itive to multi-direction and can intensify the edges with the that have same direction as the major axis. After LoG algorithm processing,the infrared targets are searched by using multi-direction gradient algorithm,choosing optimum number of gradient and searching the infrared targets using the simplest algorithm.Finally,the morphology-based algorithm was used to fill the inner space of target for const ructing the entire area of target.The results of the experiment show that the signal-to-noise r atio and contrast ratio are enhanced after processing,and the detect ion rate of the infrared targets is 1.5times larger than that with the traditional detection method.The proposed algorithm maintains the detection accuracy and reduces time-consuming. The superiority of real-time performance validates the algorithm.