In this study, AC impedance behaviors of Ti-Zr binary alloys for biomaterials have been investigated using by electrochemical impedance spectroscopy. Ti-10wt%, 20wt%, 30wt%, and 40wt% Zr alloys were prepared by arc melting and homogenized for 24 hr at 1000 °C in argon atmosphere. Phase constitutions and microstructure of the specimens were conducted by using XRD, OM and SEM. The corrosion properties of the specimens were examined through potentiodynamic test (potential range of -1500 ~ 2000 mV), AC impedance spectroscopy(100kHz~10mHz) in artificial saliva solution by potentiostat (EG&G Co, PARSTAT 2273. USA). In as-cast and homogenized Ti-xZr alloys, α-phase was identified by XRD. Microstructures were changed from lamellar structure to needle-like structure as Zr content increased. From the results of polarization behavior in the Ti-xZr alloys, it was found that the corrosion resistance was increased with increasing Zr content. From results of AC impedance spectroscopy, passive film resistance value of homogenized Ti-40Zr specimen(1.60×106 Ωcm2) showed higher than that of as-cast specimen.