Abstract: Catalysts for the synthesis of dimethyl ether from methanol dehydration was prepared，with pseudo-boehmite powder prepared by hydrothermal method as raw material.The catalysts were modified by two different zeolite molecular sieves，and the effects of molecular sieve′s species，addition amount，and ratio of SiO2 to Al2O3 on the methanol dehydration reaction were investigated.Results indicated that the catalytic activities of two kinds of catalysts modified by the two different molecular sieves were both improved; when the addition amount of molecular sieve was under 10%（mass fraction，same below），the catalyst′s activity of methanol dehydration was enhanced with the increase of addition amount and SiO2  to Al2O3 ratio；the catalyst′s activity decreased at high temperature when the addition amount of ZSM-5 reached 20%；in terms of methanol dehydration reaction，the catalyst modified by ZSM-5 had better performance in the same SiO2  to Al2O3  ratio.

Key words: molecular sieves, modification, catalyst