Abstract: The potentiodynamic scanning polarization technique was performed to investigate the corrosion behavior of a new type of medical titanium alloy Ti12.5Zr2.5Nb2.5Ta (TZNT),and three titanlum alloys in Ringer′s solution.The passive film formed on the TZNT alloy surface was analyzed.The biocompatibility for the above four alloys was evaluated by means of the subcutaneous implant test.The results show that compared with the other three alloys the TZNT alloy entered into passive state more easily.Moreover,the passive film on the alloy surface was most stable owing to its more extensive passivation potential regions and lower passive current densities,therefore the alloy had outstanding corrosion resistance.The density of inflammation cells and the thickness of fibrous membrane around the implants decreased after in vivo implantation of the TZNT and TA2 alloy in mice for 4 and 8 weeles respectively,when compared with that in the Ti6Al4V and Ti6Al7Nb alloy.The TZNT alloy had good biocompatibility.