Osteoblast-like cell response in variation with the air plasma sprayed (APS) TiO2 coating process parameters correlated with coating properties were investigated to evaluate the durability and biocompatibility of the surface-modified implant. The Taguchi technique was used to determine the coating properties affected by plasma spraying parameters on Ti-6AI-4V alloy substrate. The coating properties were characterized by porosity and surface roughness using an image analyzer and surf analyzer, respectively. The MG-63 osteoblast like cell morphology and proliferation data on TiO2 coated substrate were measured by SEM observation and direct cell counting. It was demonstrated that surface roughness increased as spray distance decreased but gas flow rates and spray distance were major factors in the case of porosity. The osteoblast adhesion morphology and proliferation data indicated that osteoblast-like cell morphology was not influenced by process parameters, but cell proliferation was affected to some extent by surface roughness and porosity among TiO2 coated specimens. Specifically, the difference between those of substrate and coating layer was relatively more visible.