Fretting wear of the titanium alloy will accelerate the formation and expansion of cracks,leading to the failure of the components in advance.The fretting wear behavior of TC4 alloy at 300 ℃ and 500 ℃ was studied by friction and wear tester.The wear scar profile and surface were analyzed by scanning electron microscope and laser confocal microscope,and the fretting wear mechanism of TC4 alloy under different displacement amplitudes at 300 ℃ and 500 ℃ was discussed.The experimental results show that under high temperature conditions,the average friction coefficient and wear rate of the specimen increase first and then decrease with the increase of displacement amplitude.In two high temperature environments,when the displacement amplitude is small,the fretting wear is in the partial slip regime,and the main wear mechanisms are adhesive wear and oxidation wear.When the displacement amplitude is 100 μm,the fretting wear is in the mixed slip regime,and the main wear mechanisms are oxidation wear,delamination wear and plastic deformation.When the large-scale mounting value,the micro operation area is in the slip regime,and the main wear mechanism is abrasive wear and fatigue wear.When the displacement amplitude is large,the fretting wear is in a complete slip area,and the main wear mechanisms are abrasive wear and fatigue wear.Comparing the wear results at 300 ℃ and 500 ℃,it shows that the higher the temperature,the better the wear resistance of TC4 alloy.This is mainly because the oxides TiO2 and Fe2O3 generated by friction play a role to protect the wear surface.