The　welding　spot　of　Ultra-high　strength　steel　of　22MnB5　and　common　steel　of　St16　were　the　investigative　objects,　the　intermediate　frequency　inverter　&　electric　servo　welding　system　was　used　to　weld　the　sheets.　Electrical　measuring　test　method　was　used　on　spot-welded　joint　under　tensile-shear　load　to　determinate　the　strain　of　different　positions,　including　the　strain　of　weld　nugget,　the　stain　around　the　nugget　and　the　base　metal＇s　strain　near　the　weld　nugget.　The　deformation　regularity　of　spot　welding　joints　surrounding　and　base　metal　were　analysed　according　to　the　data.　The　test　provided　a　reference　for　the　numerical　simulation　of　spot　welding　model.　Test　results　show　that　the　strain　distribution　on　spot　welding　joint　is　not　uniform,　the　strain　of　the　weld　nugget　center　is　relatively　small,　large　deformation　exists　mainly　in　the　heat　affected　zone.　That　is　to　say,　the　area　near　the　spot-welding　joint　heat　affected　zone　is　prone　to　yield.　The　base　metal　area　near　the　weld　nugget　is　mainly　affected　by　tensile　strain,　and　the　strain　increases　with　the　increasing　of　the　load.　The　force　condition　of　the　specimen　is　complicated　around　the　nugget,　the　relationship　between　the　load　and　the　strain　is　erratic.　The　strain　of　the　weld　nugget　will　gradually　change　from　axial　compressive　strain　to　axial　tensile　strain.　The　strain　of　spot　welding　specimen　made　of　dissimilar　materials　(22MnB5&　ST16)　is　negative,　and　almost　linearly.　©　(2013)　Trans　Tech　Publications,　Switzerland.