Multi-stage　variable　amplitude　load　with　low-high,　high-low　and　low-high-low　were　applied　to　tension-shear　spot　welding　specimen,　and　natural　frequency　were　obtained　during　fatigue　process.　Damage　accumulation　and　effects　of　loading　sequence　on　fatigue　life　were　analysed　according　to　experimental　lives　and　change　of　natural　frequency.　Experiment　results　shows　loading　block　shape,　namely　loading　sequence,　has　few　effect　on　fatigue　life,　and　life　predicted　with　linear　damage　accumulation　rule　agrees　well　with　experimental　lives.　Changes　of　natural　frequency　can　be　used　to　detect　damage　during　fatigue　process,　and　define　damage　extent.　Fatigue　lives　predicted　according　to　the　damage　evolution　principle　of　damage　mechanics　were　identical　to　experimental　results.