Wear behaviors of MoSi2 against Al2O3 or SiC under 30N at 1000°C in air have been investigated by using an XP-5 type High Temperature Friction and Wear Tester. The worn surfaces and phases of samples were characterized by scanning electron microscope (SEM) and X-ray diffractometer, respectively. Result shows the wear rate and friction coefficient of MoSi2 decreases with the increase of sliding speed. SiC is superior to Al2O3 as the counter-face materials of MoSi2. Serious adhesion leads to very high wear rate of Al2O3 in this experiment. SiC shows a surprising mass weighing phenomenon, which is caused by oxidation. The main wear mechanism of MoSi2 against Al2O3 is oxidation and adhesion. However when against SiC, it is chiefly controlled by grinding.