_{: The fretting fatigue characteristics of ultra-fine grain pure titanium under cylindrical-plane contact were studied by using a fretting fatigue experimental fixture designed by ourselves, and the effect of cyclic stress on its fretting fatigue life was analyzed. The fretting damage mechanism was analyzed by observing the wear and fracture morphology of the contact zone.The fretting fatigue life of ultra-fine grain pure titanium decreases with the increase of cyclic stress when the normal load is constant. The fretting fatigue crack originates at the edge of the contact zone, and the wear zone breaks seriously and has abrasive particles attached to it, which accelerates the fatigue failure of the specimen under the action of abrasive wear. The fracture surface shows both fatigue morphology and fretting morphology. The morphology changes from smooth to rough to fracture, the crack increases from small to large, the crack growth rate increases gradually, and there are secondary cracks in the crack propagation zone. Between the crack propagation zone and the fracture zone due to uneven force,there is a ridge-like morphology.}