The damping capacities of B/Al composite subjected to thermal-mechanical cycling (TMC) were studied. The damping capacities, including the mechanical loss Q-1 and the logarithmic decrement δ , increase with increasing the TMC cycles. The damping capacities of B/Al composite increase more greatly under the elevated applied stresses at the same temperature interval and cycles. After the TMC, the damping capacities can increase 10 times than that of as-fabricated B/Al composite. The damping behavior of B/Al composite under the present test condition is primarily associated with the interfacial degradation during the TMC.