In this paper, the natural zeolites from Weichang area were treated with sodium hydroxide. X-ray diffractometer, infrared spectrometer, N₂ adsorption-desorption technique and scanning electron microscope were employed to characterize the materials, water vapor adsorption method was adopted to evaluate the hydrophilicity of materials, and Cr and Mn ions were used to determine the ion exchange property of materials. The effect and the mechanism of alkali treatment on structure, hydrophilicity and ion exchange property of natural zeolites were then investigated. The results show that the natural zeolites from Weichang area contain clinoptilolite, quartz and illite. Alkali treatment could decrease the SiO₂/Al₂O₃ ratio of natural zeolites, and the SiO₂/Al₂O₃ ratio gradually decreases with the increase of alkali concentration. The influence of alkali treatment on structure of clinoptilolite is higher than that of quartz and illite. The structure of natural zeolite is destroyed, the specific surface area of natural zeolite decreases and the pore volume of natural zeolite increases under high alkali concentration. The hydrophilicity and ion exchange property of natural zeolites gradually increase, accompanied by the decrease of SiO₂/Al₂O₃ ratio.