To study the effect of different hydration environments on the microstructure anisotropy of kaolin， this paper carries out the deposition experiment of different salts， acids， and aqueous solutions for kaolin （Acti-MinR PG） produced in South Carolina， USA， and measures 13 XRD spectra with the X-ray diffractometer by rotating the χ angle of the kaolin sample from 0° to 72°. The quantitative texture analysis of XRD spectra of kaolin sediments was carried out by the Rietveld method based on MAUD software. On the basis of filling the lack of quantitative （non-qualitative） analysis method of clay micro texture， the orientation distribution was determined， and the formation mechanism of the structural anisotropy from the micro perspective was expounded. The results of the study reveal that pH and ion concentration have an effect on the arrangement of kaolin particles. With the increase of ion concentration in the salt solution， the weakening of electric double-layer repulsion makes the particles form an aggregation structure， which enhances the preferred orientation of kaolin and makes the soil show strong structural anisotropy. With the decrease of pH of the solution， the electrostatic attraction between the edge-face association promotes the formation of flocculation of particles and weakens the preferred orientation of kaolin.