In this study, pure Fe was surface-modified by Ta ion implantation with different incident ion doses. Its surface morphology and chemical composition were investigated using atomic force microscopy and auger electron spectroscopy. Results showed that Ta ion implantation led to the formation of Ta/Fe oxide mixtures at the outmost surface (60–80 nm in thickness) of the implanted layer. Results from electrochemical measurements and immersion tests indicated that the corrosion rate of the pure Fe in simulated body fluids can be accelerated after the Ta ion implantation. The in vitro cell culture results showed that the cytocompatibility of osteoblasts on the pure Fe has been significantly improved by applying the Ta ion implantation.