A series of (Cu0.94La0.06)(2)SnO4 photocatalysts were prepared under different calcination temperatures using a simple co-precipitation method. The crystalline structures of the as-prepared photocatalysts, as well as their particle sizes, photo absorption, and the effect of calcination temperature, were investigated using x-ray powder diffraction, Brunauer-Emmett-Teller method, transmission electron microscopy, and UV-Vis diffuse reflectance spectroscopy, respectively. The photocatalytic activity of (Cu0.94La0.06)(2)SnO4 nanocomposite oxide was evaluated using the photodegradation efficiency of acid blue 62 (AB62) as a probe under simulated sunlight irradiation. The photocatalytic experimental results show that the maximum specific photocatalytic activity of the (Cu0.94La0.06)(2)SnO4 photocatalyst appears after calcination at 450 A degrees C for 2.5 h because of the good crystallization and small crystal size of the sample. Under simulated sunlight irradiation, the AB62 aqueous solution can reach a degradation rate of 97.71% in 2 h, showing that the (Cu0.94La0.06)(2)SnO4 nanocomposite photocatalyst has a much higher photocatalytic activity than the standard Degussa P25 photocatalyst.