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With micro-arc oxidation technique,the high hardness ceramic oxide layer( MAO) was prepared on the surface of TC4 alloy,and the fretting wear behavior of TC4 alloy substrate and micro-arc oxide ceramic layer under two different displacement amplitudes was studied. The results show that,when the displacement amplitude increases from80 μm to 150 μm,the fretting damage mechanism of TC4 substrate changes from adhesive wear and abrasive wear to fatigue wear and oxidation wear,while the damage mechanism of micro-arc oxide ceramic layer is always dominated by oxidation wear. When the displacement amplitude is 80 μm,the wear amount of TC4 substrate and micro-arc oxide ceramic layer is small,but the friction coefficient is high and fluctuates greatly. When the displacement amplitude is150 μm,the wear amount increases to different degrees,while the friction coefficient decreases slightly and tends to be stable. Compared with those of TC4 alloy substrate,the average friction coefficient of micro-arc oxide ceramic layer is small,the wear profile is shallow,and the wear amount is only 70% of that of titanium alloy substrate. In summary,the results show that the micro-arc oxide ceramic coating can protect the surface of titanium alloy and effectively improve the wear resistance of TC4 alloy.