In the present investigation nano-structured TiO 2 and Fe 3 O 4 coatings produced using HVOF thermal spraying. Their photo-catalytic characteristics were consequently evaluated. Different weight percent of TiO 2 nanopowder (75vol. % anatase, 25vol. % rutile) and commercial Fe 3 O 4 powder were mixed together and used as feedstock powder and precipitated on stainless steel 316 substrate. The structure, morphology, surface and photo-catalytic characteristics of TiO 2 -Fe 3 O 4 coatings (using different Fe 3 O 4 concentration), were investigated using scanning electron microscopy (SEM), X-ray diffractometer (XRD), UV-VIS-NIR spectroscopy and Fourier transform spectrometer (FT-IR). Furthermore, the conversion rate of xylene under VIS and UV irradiation was also studied in order to evaluate the photo-catalytic activity, photo-catalytic efficiency and the stability of coatings in gas dynamic photo-reactor. Results showed that the optimum value of Fe 3 O 4 concentration affect the photocatalytic properties of TiO 2 -Fe 3 O 4 coatings in UV and visible light range. The optimum value of Fe 3 O 4 concentration depends on the coatings’ application. For instance, since it is important to change the pollution levels in short period, a minimum photo-catalytic activity constant is the best choice. However, by ignoring the period of time the right selection is a sample with the highest efficiency. It is Noteworthy that choosing a right composition of the coating is an important Keywords : Nanophotocatalyst, Titanium Dioxide, Iron Oxide, HVOF.