On　the　basis　of　finite　element　analysis,　the　variation　of　natural　frequency　is　studied　for　shear　loaded　two-spot　welded　specimens　during　the　crack　propagation　process.　The　crack　area　is　used　to　define　the　damage,　with　which　established　the　relationship　between　the　damage　and　the　natural　frequency　variation　ratio.　The　residual　fatigue　lives　of　specimens　undergone　a　certain　stage　of　fatigue　damage　are　predicted　according　to　the　damage　evolution　principle　in　damage　mechanics.　The　results　showed　that　the　proposed　damage　parameter　can　describe　the　fatigue　process　for　the　two-spot　welded　joints.