Polymer nanocomposites have elicited extensive research efforts due to their potential to exhibit spectacular properties. In the presentwork,mixtures of four different concentrations (2.5, 5, 7.5, and 10 wt%) of titaniumoxide (TiO2) nanoparticles with poly (methyl methacrylate) (PMMA) were prepared. Fourier transform infrared spectroscopy (FTIR) and optical analysis were employed to characterize and reveal the miscibilitymap and the relationship of the structure properties. From the obtained results, it is clear that the TiO2 nanoparticles have a great effect on improving the performance properties of PMMA greatly depends on the concentration of nanoparticles. Moreover, the organic parts are attached with the inorganic parts in the PMMA/TiO2 nanoparticles composites.