A novel method for the preparation of a CdS photocatalyst is presented. In this method, freshly prepared CdO obtained by decomposing cadmium acetate at a certain temperature was subjected to thermal treatment in the presence of H2S, which results in the formation of a highly stable and active CdS photocatalyst. In comparison to conventional preparation methods, CdS prepared by our method was found to be stable against both air oxidation and photocorrosion during a photocatalytic reaction. Most importantly, the special nanostep structure was observed at the surface of the sulfide photocatalyst, which was demonstrated to be crucial for the remarkable enhancement of photocatalytic hydrogen production. The apparent quantum yield at 420 nm and the energy conversion efficiency in the whole visible light region were determined to be 24.1% and 6.35%, respectively, in our experimental conditions.