Fatigue　life　analysis　was　carried　out　on　spot　welds,　taking　into　the　effect　of　welding　process　on　local　metal　mechanical　properties　within　heat　affected　zone.　Considering　the　relationship　between　material　strength　and　cyclic　stress　strain　parameters,　life　prediction　with　Pollard＇s　equation　gave　results　with　errors　in　2　factors,　as　well　as　Barkey＇s　data.　Experimental　results　were　further　studied　with　Manson-Coffin　damage　equation.　Results　showed　that　the　metal　mechanical　properties　gradient　have　implicit　effect　on　crack　initiation　site,　cannot　be　neglected　in　fatigue　life　prediction.