Al-pillared interlayered montmorillonite ( Al-PILM) was prepared using the artificial Na-montmorillonite from the Qingfengshan bentonite mine as a starting material mixed with Al-pillaring solutions. The microstructure of the materials was stndied by an X-ray powder diffractometer and a Fourier transform infrared ( FTIR ) spectrometer. The results indicated that the basal spacing [ d (001) value ] of the materials was increased significantly to 1.9194 nm relative to Na-montmorillonite (1.2182 nm). After calcined for 2 h at 300℃, the basal spacing was stabilized at 1. 8394 nm and the layered structure of the materials was not destroyed. Thermal analysis was conducted by a thermal gravimetry and differential thermal analysis ( TG - DTA ) instrument, it showed that Al - PILM lost physically adsorbed water below 230.6℃ and water formed by dehydroxylation of the pillars at around 497.1℃, with a peak of the phase transformation at 903.0℃.