Of　particular　importance　and　interest　are　the　effects　of　pulsed　Nd:YAG　laser　beam　welding　parameters　on　penetration　and　microstructure　characterization　of　DP1000　butt　joint,　which　is　widely　used　in　the　automotive　industry　nowadays.　Some　key　experimental　technologies　including　pre-welding　sample　preparation　and　optimization　design　of　sample　fixture　for　a　sufficient　shielding　gas　flow　are　performed　to　ensure　consistent　and　stable　testing.　The　weld　quality　can　be　influenced　by　several　process　factors,　such　as　laser　beam　power,　pulse　duration,　overlap,　spot　diameter,　pulse　type,　and　welding　velocity.　The　results　indicate　that　these　key　process　parameters　have　a　significant　effect　on　the　weld　penetration.　Meanwhile,　the　fusion　zone　of　butt　joints　exhibits　obviously　greater　hardness　than　the　base　metal　and　heat　affected　zone　of　butt　joints.　Additionally,　the　volume　fraction　of　martensite　of　dual-phase　steel　plays　a　considerable　effect　on　the　hardness　and　the　change　of　microstructure　characterization　of　the　weld　joint.