In this work, we report synthesis and characterization of Bi2O3 nanoparticles loaded on mesoporous MCM-41 nanoparticles by a simple solid-state dispersion (SSD) method. Monoclinic bismuth oxide nanoparticles were prepared by polyacrylamide gel method and used as loading materials on the prepared mesoporous MCM-41 as a supporting material. Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD) and transmission electron microscopy (TEM) and the high resolution transmission electron microscopy (HRTEM) were used to study the structural and morphological characteristic of the prepared nanocomposite samples. Photocatalytic performance of the prepared samples was finally evaluated by degradation of methylene blue under irradiation of UV and visible light. The results revealed that, Bi2O3 loaded on nanosize MCM-41 has higher photocatalytic activity than that of pure starting Bi2O3 nanoparticles.