In this study, titanium dioxide nanostructures (TiO2) were synthesized by the microwave-assisted method and the structural, purity, morphological and optical properties are analyzed by thermal analysis (TGA-DTA), X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM) and UV-Vis spectroscopy. The influence of light intensity and the stirring rate on the photocatalytic activity of TiO2 nanostructures were investigated for the removal of methylene blue from water. The results show that by increasing the intensity of light the photocatalytic activity of TiO2 nanostructures increases intensively. At low-intensity radiation, the results show that the stirring rate multiplies the photocatalytic activity of TiO2 nanostructures, while at high-intensity radiation, the stirring factor has a negligible effect on the photocatalytic activity of TiO2 nanostructures. As a result, the radiation intensity is a determinant factor in the photocatalytic activity of nanostructures compared to the stirring rate.