This study investigated the antibacterial activity and cell adhesion of commercially pure titanium (Ti) surfaces modified by zinc plasma immersion ion implantation (Zn-PIII) treatments for dental implant application. An X-ray photoelectron spectrometer, atomic force microscope, and scanning electron microscope were utilized to analyze the chemical composition and surface topography of Zn-PIII Ti specimens. Porphyromonas gingivalis (P. gingivalis), common oral bacteria which often cause complications in combination with dental implantation, were seeded onto the modified Ti surfaces for 48h in order to study the antibacterial effect of the surface. The attachment and proliferation of murine osteoblasts (MC3T3-E1) on the Zn-PIII Ti surface were investigated using acridine orange fluorescence staining and a scanning electron microscope. The results showed that the Zn-PIII treatment influenced the surface topography of the Ti specimens, and that Zn singles on Zn-PIII-treated Ti surfaces increased with increased Zn-implanted time. The numbers of bacteria that adhered to Zn-PIII-treated Ti surfaces were significantly less than for untreated Ti, and gradually decreased with increasing Zn concentration. In addition, the adhesion and proliferation of MC3T3-E1 on Ti were improved by Zn-PIII treatment (p < 0.05). The results suggest that the Zn-PIII modified surface-layer-formed Ti could consequently restrain bacterial adhesion of P. gingivalis, and could enhance the cell proliferation and adhesion to Ti surfaces for dental implant application.