The　characteristics　of　large　resistivity,　high　peak　temperature　in　welding　thermal　cycle,　fast　rising　rate　of　temperature　and　uneven　local　cooling　rate　determined　the　heterogeneity　in　resistance　spot-welded　joints　of　hot　stamping　boron　high　strength　steel,　which　resulted　in　three　different　failure　modes　of　the　joints.　The　effects　of　welding　time　on　microhardness,　bearing　performance,　failure　modes　of　the　resultant　joints　were　studied,　and　the　failure　mechanism　was　investigated.　The　results　show　that　the　capacities　of　bearing　and　energy　absorption　between　400　ms　and　600　ms　of　welding　time　were　equivalent,　and　the　nugget　pull-out　could　not　be　the　standard　for　evaluating　the　quality　of　joints.　The　welding　defects,　stress　concentration　and　local　toughness　deterioration　in　HAZ　were　three　main　factors　that　affected　the　failure　of　the　joints.