Nanometer size zinc oxide (ZnO) powder was prepared by a novel "solution-combustion method (SCM)", and it was used as a semiconductor photocatalyst to evaluate its photoreduction properties. Aqueous solution of heavy metal ions (Cu-EDTA) was used for the photocatalysis reaction under UV illumination. The result was then compared with other semiconductor photocatalyst powders such as titanium dioxide (TiO2) powder (P25; Degussa) and TiO2 powder prepared by a homogeneous precipitation process at low temperature (HPPLT). The zinc oxide nanopowder showed the highest removal rate of the Cu++ ions from the solution among the photocatalyst powders compared. The superior photoreduction ability of the ZnO nanopowder appears to be due to its excellent UV absorption capacity.