Different properties of nanostructured materials such as physical, chemical and catalytic properties based on metal nanoparticles for various applications have been studied extensively on account of their attraction these days. Nanocrystalline tungsten oxide (WO2) can chemically break down adsorbed organic contaminants in sunlight. In this research work, a novel photocatalyst of WO2/glass mat nanocomposite has been prepared by hot filament chemical vapor deposition (HFCVD) method, which is used for the degradation of dyestuff from dyes wastewater. Morphology of treated mat was observed using a scanning electron microscope (SEM). The amounts of tungsten oxide on glass mat were examined using the energy dispersive X-ray (EDX) method. Electrical surface resistivity was also measured. It is concluded that oxidant sedimentation has been done physically without any structural changes and increasing of reaction time led to an increase in deposition of tungsten oxide and finally led to a decrease in the electrical resistance of glass mat. The photocatalytic activities of tungsten-oxide-deposited glass mat were assessed by analyzing the decrease in concentration of the methylene blue (MB) as a colorant after exposure to ultraviolet (UV) irradiation. The MB concentration decreases continuously, concomitant with the UV irradiation time up to 240 min. The results show that the WO2/glass mat nanocomposite exhibits high photocatalytic activity and provides a good way in the degradation field of dyes wastewater.