Objective The purpose of this study was to investigate the fibronectin adsorptive capacity of pure titanium surfaces and improve their biological properties by regulating their surface charge. Methods The different surfaces of titanium sheet were obtained by sandblasting with large grit and acid- etching (SLA), and then immersing in different solutions. Surface morphology, elemental composition, roughness, and urface charge status were studied, and fibronectin adsorption assay was performed for comparative analysis. Result The surface morphology of each group was similar, but the surface elements of the different groups were different because of immersion in different liquids. There was no significant difference in the surface roughness of each group. Titanium sheets immersed in calcium chloride solution had the highest protein adsorption capacity (P < 0.01), whereas the control group had the lowest adsorption capacity. Conclusions Immersin. Of titanium sheets in calcium chloride solution containing divalent calcium ions can change their surface charge, enhance their protein adsorption capacity, and improve their biological properties.