Silver ion was added to liquid feedstock to deposit Ag+ doping nanostructured TiO2 photocatalytic coatings through liquid flame spraying. The coating microstructure was characterized by X-ray diffraction (XRD). The photocatalytic performance of coatings was examined by photodegradation of acetaldehyde. XRD analysis showed that the phase structure of coatings was not significantly influenced by the silver ion doping. However, a shift was found for XRD peaks of anatase TiO2. The photocatalytic activity of the TiO2 coatings was increased and then decreased with the increase of dopant concentration. The photocatalytic activity of doping coatings was higher than that of pure TiO2 coating, in spite of dopant concentration. The enhancement of photocatalytic performance of doping coatings is attributed to co-doping of Ag+ ion and metallic Ag.