Abstract: Corrosion-wear behaviors of TC4 alloy sliding against alumina in artificial seawater was investigated. The wear volume was determined by weight-loss method. The synergistic effect between corrosion and wear can be obtained by measuring the material loss under cathodic protection and the corrosion rate under sliding condition. In this paper, the wear caused by corrosion wear was higher than that under cathodic protection, and this was the evidence of synergistic effect. The fact that the ratio of the mechanical wear to the total wear ranged form 65.9% to 89.8% indicated mechanical wear prevailed in the corrosion-wear process. The ratio of the synergistic effect between corrosion and wear to the total wear was between 10.2% and 34.1% and therefore can not be neglected.