Polyaniline silica nanotubes (PANI@SNT) were prepared by in situ polymerization of anilinium ion adsorbed on the surface of silica nanotubes (SNT), which acted as a template. After polymerization, the silica templates were intensively removed with HF solution to give closed polyaniline nanotubes (PANI-NT). Interestingly, the PANI@SNT showed pH-responsive redox reversibility.