Because of the relative far distance between infrared imaging system and target or the wide field infrared optical, the imaging area of infrared target is only a few pixels, which is isolated or spots to be showed in the field of view. The only available is the intensity information (gray value) for the target detection. Simultaneously, there are many shortcomings of the infrared image, such as large noise, interference and so on, therefore the small target is always buried in the background and noises. The small target is relatively difficult to detect, so generally, it is impossible to make reliable detection to this target in a single frame image. Summarily, the core of the infrared small target detection algorithm is the background and noise suppression based on a single frame image. Aiming at the infrared small target detection and the above problems, a shearlets-based background suppression algorithm for infrared image is proposed. The algorithm demonstrates the performance of advantage based on shearlets, which is especially designed to address anisotropic and directional information at various scales. This transform provides an optimally efficient representation of images, which is greatly reduced the amount of the information and the available information representation. In the paper, introducing the principle of shearlets first, and then proposing the theory of the algorithm and explaining the implementation step. Finally, giving the simulation results. In Matlab simulations with this method for several sets of infrared images, simulation results conformed to the theory on background suppression based on shearlets. The result showed that this method can effectively suppress background, and improve the SCR and achieve a satisfactory effect in the sky background. The method is very effectively for target detection, identification, track in infrared image system for the future.