As traditional infrared image denoising methods usually achieve the satisfactory effect at the cost of damaging the image content, an infrared image denoising method based on adaptive over-complete sparse representation is presented. The image can be decomposed via orthogonal matching pursuit algorithm into the content part and the remainer on the adaptive dictionary trained by the K-SVD method in allusion to the infrared image, eventually the infrared image can be reconstructed by the content part. Experimental results show the effectiveness of the method.