Chitosan/titanium oxide nanocomposite (CS/TiO2 nanocomposite) could be prepared by different physical and chemical methods for various applications. CS/TiO2 nanocomposite has been chemically prepared via microwave heating technique and physically prepared through solution mixing method. Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction spectroscopy (XRD), transmission electron microscopy (TEM) and dynamic light scattering (DLS) were used as spectral tools to characterize the functionality, phase, morphology and particles size of the prepared nanocomposites, respectively. The thermal stability was investigated by the thermogravimetric analysis (TGA), while optical properties were studied using ultraviolet-visible spectroscopy (UV-vis).The results have confirmed that CS/TiO2 nanocomposite was chemically and physically prepared via the outer sphere complexation and the electrostatic repulsion between chitosan and titanium oxide nanoparticles surface (TiO2 NPs), respectively. The thermal stability was enhanced with nanocomposite prepared by chemical method when compared to that prepared by the physical method. In addition, a significant shift in the peak of the chemically prepared nanocomposite from the UV region to visible region was observed. This shift could be attributed to the surface modification of TiO2 NPs by the chemical reaction.