The effects of Na~+ in dilution steam and coke deposition on the physicochemical properties and catalytic performance of ZSM-5 catalysts for the methanol-to-propylene(MTP) reaction were investigated. The deactivated and regenerated catalysts were characterized by means of X-ray diffraction(XRD), scanning electron microscopy(SEM),X-ray fluorescence(XRF) spectrum,nitrogen adsorption/desorption, temperature-programmed desorption of ammonia(NH_3-TPD),and thermogravimetry(TG).Their catalytic performance for MTP reaction was tested in a continuous flow fixed-bed micro-reactor at 470℃,101325 Pa,and with methanol weight hourly space velocity(WHSV) in the range of 1.0-3.0 h~(-1).The results indicated that the catalyst crystal structure and morphology was not significantly altered after 970 h on stream.In the MTP reaction,Na~+ in the dilution steam can easily enter the pore channels of the catalyst, and partially replace H protons,thereby gradually decreasing the amount of acidity and acid strength of the catalyst,which eventually causes deactivation.In addition,coke deposits on the catalyst surface blocking its micropores are the main reason for deactivation of the MTP catalyst.Coke deposits are mostly eliminated through the burning charcoal regeneration process.The effect of framework dealumination from the catalyst by steam in the MTP process is slow but more serious.Through regeneration and ion exchange process,the catalytic activity of the deactivated catalyst can be fully restored.The conversion of methanol is consistently above 99%,and propylene selectivity is greater than 46%even after 470 h on stream.With increasing reaction time,the propylene selectivity gradually increases,while ethylene selectivity gradually decreases.