Remote sensing image fusion is one of the effective ways to solve multi-source remote sensing data integrated performance. ASTER multi-spectral image is better at spectral information than TM and CBERS-1, except for the lack of spatial resolution. The fusion of SPOT pan and ASTER multispectral is significant. Here, we choose the PCA transform, Brovey transform, Gram-Schmidt (GS) transform and wavelet transform fusion method to compare. The results show that the PCA transform and GS transform are suitable for the fusion of SPOT5 pan and ASTER multi-spectral image.