A hierarchical hybrid micro/nanostructure was produced on the surface of titanium (Ti) implants by combined use of acid etching and anodic oxidation. The bioactivity of the modified Ti was evaluated by a simulated body fluid (SBF) soaking test and in vitro cell culture experiments. The results showed that the surface-modified Ti implants had a microstructure with enhanced surface roughness. There was also a nanostructure superimposed on the microstructure, forming a hierarchical hybrid micro/nanostructure. The modified Ti accelerated the Ca–P mineralization deposition on their surface in SBF, and promoted osteoblast adhesion, proliferation, and bone-related gene expression compared to the polished Ti and the Ti implants subjected only to acid etching or anodic oxidation, which was ascribed to the synergistic effects of both micro- and nanotopography generated. This study provides a simple and cost-effective approach to enhance the bioactivity and biocompatibility of orthopaedic implants, and points out the importance of both micro and nanotopography.