The　relative　changes　of　natural　frequency　and　relationship　with　fatigue　damage　were　investigated,　based　on　3D　finite　element　simulation　and　the　dynamic　response　experiments　for　tensile-shear　double-spot　welded　joints　during　the　fatigue　damage　process.　The　results　of　the　simulations　showed　that　a　good　agreement　was　achieved　with　experimental　analysis.　3D　finite　element　simulation　can　reflect　the　changes　of　natural　frequency　for　double-spot　welded　joints　during　the　fatigue　damage　process.　Based　on　experiments　and　finite　element　simulation,　a　fatigue　damage　equation　was　proposed,　which　can　be　used　to　calculate　the　damage　of　double-spot　welded　joints　in　the　fatigue　process.