In the cell microenvironment, cells experience simultaneously a range of chemical, topographical and biological signals. Therefore, it is important to create model surface that allow for examining the combined effect of these signals. In this study, we fabricated surface nanotopography gradients via surface immobilization of gold nanoparticles in a number density manner, thereafter, we tailored the outermost surface chemistry through deposition of a very thin plasma polymerized film with certain chemical composition (allylamine or acrylic acid) over the surface bound nanoparticles. The co-effect of surface topography and surface chemistry on osteoblast-like SaOS-2 cells adhesion, spreading and differentiation was studied in vitro. The surface nanotopography was found to have more dominant effect on initial cell adhesion and spreading than the outermost surface chemistry employed in this study. However, we also found that surface topography and surface chemistry synergistically regulated osteogenic differentiation. This study illustrates the use of plasma polymerization as a tool to generate unique models surfaces that allow for examining the co-effect on surface nanotopography and chemistry on cell behaviors. Furthermore, this study also provides reference for the utility of plasma polymerization as a method of surface modification for bone tissue engineering scaffolds and/or orthopedic implants.