Fusobacterium nucleatum (F. nucleatum) is a gram-negative obligate anaerobe bacterium that threatens human periodontal health. It can cause many oral diseases, including periodontitis, gingivitis and peri-implantitis, and even some diseases such as colorectal cancer are related to it. This paper aims to develop a novel and simple surface modification method for anti-Fusobacterium nucleatum on titanium, i.e., the material for implants. In this study, different concentrations (0.0–1.0%) of PHMB were dip-coated on the titanium surface. The surface properties were examined with the aid of Scanning electron microscopy, Energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, and the antibacterial property against F. nucleatum was investigated using colony-forming unit. It was found that the PHMB successfully formed a self-assembled coating on the titanium surface and the PHMB-coated titanium had a strong capability of inhibiting F. nucleatum. Even though differences were found among the several concentrations, PHMB exhibited promising results as a simple coating strategy for dental implants.