Abstract: Image fusion algorithms have evolved from traditional image fusion method, pyramid based method to nowadays wavelet based image fusion methods. The current wavelet based fusion algorithms are based on Mallat algorithm and à trous algorithm, and it deals with dyadic wavelet theory. The fundamental principle of those algorithms are:in frequency domain,substituting high resolution panchromatic image's low pass half band frequency w ith TM multi-spectral image's frequency,and then using invert Fourier transform to get fused image. But as the resolution ratio between SPOT PAN and TM image is 1:3,it is not proper to use dyadic wavelet to solve this fusion problem. Zhu C Q has reported his research which is based on M-band theory, but M-band Mallat algorithm will lead to phase distortion in image fusion process. Wang Z J(2000)introduced MRAGM algorithm which is also based on M-band theory and can deal with any integer ratio of two images. This paper explains how to use MRAGM algorithm to fuse SPOT-P and TM-M. The result show s MRAGM improves the spatial resolution of multi-spectral images while keeps the hue unchanged. The key problem to use this algorithm is to designe compactly supported K-regularity M-band scale function filter.