4.conclusion In summary, TiO2 nanotubes arrays were successfully fabri cated on titanium, which is widely used for orthopedic implants in fluorine-containing anodization.Tio2 nanotubes were the most highly-ordered when using high viscousselectrolyte in anodization with the application of pulse potential. This method is environ- ment friendly, simple and repeatable. Length of the nanotubes could be significantly controlled from about 250nmto1pm. More- over at tube length around 560nm(anodized for 1.5h the highest adhesion of HA surface on the nanotube was achieved.Ti02 nano- tube arrays can improve both adhesion of HA on the modified implant and the surrounding bone tissues in vivo, which is essen tial for early bone formation. The LivelDead cell staining study on anodized titanium, which fabricated from this study.also supports this hypothesis.