In order to study the antibacterial properties of bioactive Ti and its mechanism, alkali-heat treated titanium (AH-Ti) was implanted in rat with Staphylococcus aureus suspension to make infection with pure titanium as contrast. The myeloperoxidase activity was detected for evaluating the rat’s inflammation. The concentrations of albumin and fibrinogen were measured by the Enzymemultiplied immunoassay technique. The results show the AH-Ti related inflammation is low along with low albumin and fibrinogen. It is proved AH-Ti has good antibacterial property in vivo. The mechanism for AH-Ti to prevent bacteria adhering to its surface is that its selectively absorbing albumin to its surface weakens the inflammation around the AH-Ti, and the fibrinogen concentration is lower in turn