The results of an almost simulatenous observation of the 22 GHz H2O maser and the 43 GHz SiO masers in M type stars are presented. A systematic change of H2O maser spectra which shows the expansion of maser emitting region was found. Except for massive stars, the expansion velocity of the H2O maser correlates with the IRAS 12/25 micron intensity ratio that is thought to be correlated with the mass loss rate. These results are interpreted by the collisional excitation model calculated by Cooke and Elitzur and the authors' H2O maser's beaming model. Also the blocking effect of red shifted H2O maser emission are discussed.