Infrared complex background suppression is an important part of infrared dim target detection, which directly affects the target detection probability and false alarm rate of subsequent algorithms. As the isotropic bilateral filtering background suppression method can not change the background prediction direction and remain a large residual in the direction of the structured cloud edge, in this paper, an anisotropic bilateral filter which adapts the filter parameters including filter scale, mask size and filter direction by using the local characteristics of the image was designed. It separates the target from background more precisely. The test results show that the proposed method has a signal to cluter ratio gain for target and a background suppression operator for clutter, and both are up to 4 with the input signal to clutter ratio of 4.