Abstract: Aiming at solving the problem of very high cycle fatigue for the aero-engine in the corrosive environment, accelerated corrosion treatments were performed on TC17 titanium alloy, and the effect of corrosion on very high cycle fatigue properties of TC17 titanium alloy was studied by using the ultrasonic fatigue testing system at room temperature. The experimental results indicate that the pre-corrosion and without-corrosion specimens tested to failure in the range above 107 cycles did not show obvious fatigue limit and express the fatigue fracture. The fatigue strength reduced a little for the pre-corrosion specimen, and the S-N curves were much close to each other for the two kinds of specimens with the increase of the cyclic number. The fatigue sources were all located at the surface of specimens after corrosion, the pitting caused by destructive oxidation film was the main reason of fatigue cracks initiation on the surface.