The bending fatigue of Al6061 alloy has been evaluated by the acoustic nonlinearity of laser-generated surface wave. The surface wave is very attractive for field applications since it enables to pulse and receive signals at the same surface of materials, and has strong acoustic nonlinear effects on the surface. A relative acoustic nonlinear parameter was measured successfully on the surface of fatigue-damaged aluminum 6061 alloy. The results show that the acoustic nonlinear parameter increased with fatigue damage accumulation in relation to dislocation evolution. Consequently, this study suggests that the acoustic nonlinearity technique of a laser-generated surface wave can be potentially used to characterize surface damage resulting from bending fatigue.