Al-pillared-montmorillonite (AlPMt)/poly(methyl methacrylate)(PMMA) nanocomposites were synthesized via melt blending method (MBM) and solution blending method (SBM). FTIR-ATR spectroscopy proved the interaction of AlPMt with PMMA polymer matrix. The thermogravimetric and differential scanning calorimeter analyses showed that the thermal stability and the glass transition temperature (Tg) of polymer matrix shifted to higher temperatures with increasing AlPMt content. Images showed that AlPMt dispersed at nanometer scale in polymer matrix. Contact angle measurements demonstrated that the hydrophilicity of the PMMA increased with incorporation of AlPMt. However, the thermal stability of clay/polymer nanocomposites (CPNs) was significantly changed with CPN preparation method.