In this work, we systematically studied the tribological behaviors of MoAlB ceramic under different counterpart materials (Al2O3, Si3N4, SiC and 316L) in artificial seawater. MoAlB ceramic exhibits high wear rates when sliding against Al2O3 and Si3N4 because of the high Hertzian contact stress, but a thin layer of Al(OH)(3) gel film contributes to a low friction coefficient of 0.19 for MoAlB/Al2O3 tribopair; when sliding against 316L, the large hardness difference and severe adhesion of 316L lead to a highest friction coefficient but a low wear rate for MoAlB. When MoAlB ceramic slides against SiC, a lubricating hydrated silica tribofilm makes MoAlB obtain the best tribological performance with a friction coefficient of 0.12 and a wear rate of 6.63 x 10(-7) mm(3).N-1.m(-1).