By　the　fatigue　experiment　and　dynamic　response　experiment,　the　variation　characteristic　of　natural　frequency　was　investigated　based　on　the　single　tensile-shear　spot-welded　specimens　during　the　fatigue　process　with　constant　amplitude,　variable　amplitude　and　random　loading.　Frequency　response　function　curve　and　modal　natural　frequency　were　compared　during　the　fatigue　process　in　this　paper.　According　to　the　rates　of　frequency　change　and　the　residual　life　ratio,　a　fatigue　parameter　was　proposed　to　describe　the　fatigue　process　under　random　loading,　and　a　linear　relationship　was　established　between　the　rate　of　frequency　change　and　the　fatigue　parameter.　The　fatigue　life　was　predicted　on　the　basis　of　loading　spectrum,　the　rate　of　frequency　change　and　current　cycle　number.　The　proposed　method　can　be　used　in　the　situation　that　loading　spectrum　was　given　and　natural　frequency　was　measured.　The　calculated　results　showed　that　the　predicted　fatigue　lives　were　in　good　agreement　with　experimental　lives.