Objective To compare the synthetic ability of osteoblasts on the surface of different nano -granule titanium films and investigate the correlation between nanophase titanium films and cellular biocompatibility. Methods Four different nano-granule titanium films were produced by direct current magnetron sputtering, at ambient, 100 ℃, 250 ℃, 380 ℃ substrate temperature, respectively. Rat osteoblasts were seeded on the surface of four treated groups of titanium film samples and non-treated Ti sample（control group）. The production of osteocalcin（OC） in all five groups were detected by using double antibody sandwich enzyme-linked immunosorbent assay. Results The production of OC increased gradually from day 7 to day 14 in all groups. In the control group, it showed significant differences with other five groups on day 7. On day 14, the production of OC in 100 ℃ group was the highest, and it showed significant differences with 380 ℃, control group and blank group. In 250 ℃ group, the production of OC also showed significant differences with 380 ℃, control group and blank group（P＜0.05）. Conclusion Titanium with nano-modified surface had good biocompatibility and different nano-granule titanium films could affect the synthesis of osteoblasts.
