The　joints　of　RSW　for　HSHSS　were　prepared　with　IF　spot　weld　equipment.　The　weld　nugget,　fracture　mode,　microstructure　and　micro-hardness　of　the　joints　were　investigated.　The　weld　nugget　increases　and　the　fracture　mode　changes　from　interfacial　fracture　to　nugget　plug　fracture　with　the　increasing　welding　current.　There　are　three　distinct　zones　in　the　weld　joint:　weld　nugget,　heat　affected　zone　(HAZ)　and　base　metal.　The　microstructure　of　HAZ　includes　tempered　zone　(HAZ-1),　incomplete　quenching　zone　(HAZ-2)　and　complete　quenching　zone　(HAZ-3).　The　micro-hardness　of　weld　nugget　and　HAZ-3　is　same　with　the　base　metal.　The　micro-hardness　of　HAZ-1　and　HAZ-2　is　smaller　than　that　of　base　metal.