By employing KOH etching of silicon and hydrothermal growth of titanium oxide (TiO2), TiO2 nano rods assembled on the silicon micropyramids to form biomimetic composite coating, similar to moth-eye structures. The biomimetic composite coating possessed not only the micro-nano hierarchical structures but also the p-n heterojunctions, resulting in a decrease in the reflection of incident light and an increase in the separation efficiency of photogenerated carriers. Meanwhile, the structures showed excellent superhydrophilicity, making for the self-cleaning of the material surface. We further demonstrate that by exploiting the advantages of this method, the application of such structures in the photocatalysis field is thus straightforward.