According to the features of the infrared and micro-light images,a new algorithm of night-vision image fusion is proposed based on multi-wavelet transform.Firstly,two night-vision images are transformed by multi-wavelet to obtain the sub-band multi-wavelet coefficients.Then,their low-frequency coefficients are fused by using adaptive weighted fusion operator.Their high-frequency,coefficients conduct threshold denoising and sub-band enhanced,and then are fused by using frequency band direction fusion operator.Finally,the fusion image is obtained by multi-wavelet inverse transform.The experiments indicate that the performance of new algorithm is better than those of single-wavelet fusion algorithm and PCA fusion algorithm.It not only highlights the features of the edge of the image,but also significantly enhances the visibility and clarity of the image.And it has made significant improvements in objective evaluation criteria such as information entropy,PSNR etc.