Methanol production is a standard outlet for natural gas.Nevertheless, the methanol price level in the past hindered a possible extension of the usage of methanol.however, driven by the consumption of the derivatives, the need for propylene is growing faster recently.Due to the shortage and rising price of petroleum recently, developing new technologies of propylene productuion are required.Because of low methanol prices especially in china, the route over methanol to propylene (MTP) is one of the most promising new technologys.However, because of the decayed activity caused by the formation of carbonaceous deposits on the catalyst surface, which mainly is coke, developing new catalysts with higher yield of propylene and better stability for MTP is the key technology of study.Fistly, by impregnating phosphate, cerium and potassium onto HZSM-5 zeolite and carrying out the reaction of methanol to propylene in a small fixed-bed reactor, the effect of catalysts acidity on the reaction was investigated.The experiment results and the NH3-TPD profiles (Fig.1)show that, impregnating with potassium ion can partly eliminate the strong acid sites of HZSM-5 zeolite without distinct influence on weak acid sites.And this gives the catalysts better catalytic performance in the reaction of methanol to propylene.When the methanol WHSV was lh-1, the selectivity of propylene was greater than 43%, and the conversion of methanol was greater than 99% aftcr the reaction carried through for 280 h.The results of experiment exhibited that the catalysts modified by potassium ion had good prospects for industrial application.