For metallic biomaterials, surface treatment is essential for improving osseointegration. Acid etching is the basic method used for removing undesirable contaminants and increasing surface roughness. Although the obvious effect of the etching process is a change in surface characteristics, interestingly, surface etching can also affect the tensile properties of the material. In this paper, the influence of etching on the tensile behavior of pure titanium was investigated. The surface morphology and tensile properties of coarse- and ultrafine-grained pure titanium specimens were examined after hydrofluoric acid etching, in terms of the etching time. The ultrafine-grained titanium was prepared using conform equal-channel angular pressing to enhance the mechanical properties of the pure titanium. Micro-scale pores were observed, and tensile strength was decreased in the 1 min etched coarse-grained titanium. The 20 min etched coarse-grained specimen and the ultrafine-grained specimen with relatively homogeneous pore structure maintained or slightly increased their tensile strengths. These results provide a new foundation for the production of reliable metallic biomaterials.