Peri-implantitis is difficult to treat in clinical settings; this is not only because it is a site-specific infectious disease but also because it impedes osseointegration. In this study, a novel cold atmospheric pressure air plasma jet (CAPAJ) was applied to study the treatment of peri-implantitis in vitro. CAPAJ treated the samples for 2, 4 and 6 min, respectively. To evaluate the titanium surface characteristics, the surface elemental composition (X-ray photoelectron spectroscopy [XPS]), roughness and hydrophilicity were evaluated in each group. Concurrently, the sterilization and osseointegration effect of CAPAJ were also examined. Results revealed that after CAPAJ modification, roughness and hydrophilicity of titanium surfaces were significantly increased. Moreover, XPS results demonstrated that the C1s peak was reduced and N1s and O1s peaks were obviously improved. More importantly, CAPAJ showed favorable sterilization and bone formation effects. CAPAJ seemed a simpler and more efficient strategy for the peri-implantitis treatment.