Ti35 alloy has excellent corrosion resistance and can serve in the high concentration of oxidizing boiling acid medium for a long time. It is an ideal candidate material for commercial reprocessing. In this paper, the open circuit potential (OCP), the potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) of Ti35 alloy were tested by electrochemical test system in 6M nitric acid solution containing fluoride ions and the effect of the fluoride ion on the corrosion resistance of Ti35 alloy was investigated. The results show that the corrosion resistance of the alloy decreases with the increase of fluoride concentration while the alloy still exhibits good corrosion resistance in general. The critical concentration of fluoride ions affecting the corrosion resistance of the alloy is about 50 ppm. Further, the mixed potential theory is adopted to explain the undermined mechanism of the changing corrosion resistance of the alloy.