Abstract: The dealuminized mordenites with SiO₂/Al₂O₃ in the range from 16 to 186 were prepared by the method of steam with acid leaching. Their structure characteristic was studied by X-ray diffraction and IR. The lattice parameters exhibit a nonlinearity and a pronounced anisotropy with the degree of dealumination. Since parameter "a" is obviously contracted, it makes the long axis of elliptical main channel of mordenite contracted.The vibration frequencies of zeolite framework at 600-1300cm^-1 shifted to higher frequencies with dealumination. As Al/u.c. was changed from 4 to 3, the obvious change of the structure charactetistic occurred with the dealumination , it is probably related to the removal of the aluminum atoms of position "2" from the framework. When Al/u.c.≤3, the new Si-O-Si framework was formed and it was rearranged to a more orderly structure.

Key words: Mordenite, Dealumination, Structure characteristic