Abstract: According to the error and the interpolation artifact using mutual information directly for image registration，a computational method on frequency-domain for the estimation of the mutual-information is proposed combining the image spectral characteristics and the gradient ascent algorithm which is improved by bringing in the idea of annealing is used to find the peak of mutual information alternately.The correlation-length distance is used to estimate the region of the optimal parameters，and this algorithm can be initialized close to the optimal registration parameters.The results of the experiment indicate that it has obvious convergence and stability compared with traditional methods for multispectral remote sensing image.