The synergistic effects of ferric stearate, ferrocene and nickel N,N-dibuty dithiocarbamate (NiDBC) on photocatalysis were studied. Absorption intensities and redox abilities of these pholocatalyst compounds were investigated by Diffuse Reflectance Spectroscopy (DRS) and cyclic voltammetry. The study indicated that adding Ferric stearate to either ferrocene or NiDBC reduced the absorption intensity at the range of 400-550nm. Mixed with NiDBC, the absorbance ranges of ferric stearate and ferrocene were both broadened from 200-550nm to 200-700nm. The results of cyclic voltammetry indicated that redox ability of ferrocene was inhibited by ferric stearate. Furthermore, accession of NiDBC may enhance the inhibition. NiDBC reduced the redox ability of ferric stearate as well.