Clay was organically modified with one kind of ionic liquild. Organical clay obtained was used to prepare poly(propylene) (PP)/clay nanocomposites by solution blending. Flourier transform infrared (FTIR), wide-angle X-ray diffraction (XRD) and thermogravimetric analysis (TGA) revealed that the ionic liquild was loaded in the galleries of organically modified clay. TGA result show the thermal stability of organically modified clay was superior to clay. XRD patterns indicated that the d-spacing of clay layers increased to 2.96 nm from 1.22 nm of clay. XRD patterns of PP/clay nanocomposites show that clay layers were dispersed in PP matrix by nanometer size.