The　welding　characteristics　of　7075　aluminum　alloy　and　DP980　dual-phase　steel　sheet　were　systematically　studied　by　the　friction　plug-riveting　spot　welding　technology.　The　effects　of　different　welding　parameters　on　the　weld　formation,　tensile　strength,　and　microstructure　of　welded　joints　were　analyzed.　The　complete　metallurgical　joining　interface　was　formed　between　the　rivet　and　steel　plate.　A　partial　metallurgical　joining　interface　was　formed　between　the　circumferential　surface　of　the　rivet　shaft　and　the　aluminum　alloy　close　to　the　steel　sheet.　However,　the　position　of　the　rivet　head　did　not　form　a　metallurgical　joining　with　the　aluminum　alloy.　During　the　welding　process,　the　area　of　the　rivet　interface　underwent　severe　plastic　deformation　by　frictional　heat　and　down　pressure;　thus,　there　was　a　violent　interaction　between　the　plastically　deformed　metal　and　the　surrounding　aluminum　alloy.　The　molten　aluminum　infiltrated　into　the　rivet　at　the　most　of　sample　joints.　The　penetration　of　aluminum　had　a　negative　effect　on　the　shear　load.　The　maximum　shear　load　of　the　joint　was　14.374　kN.　There　were　two　types　of　fractures:　the　internal　fracture　of　the　rivet　and　the　fracture　of　the　steel/steel　friction　interface.　When　the　fracture　mode　was　an　internal　fracture　of　the　rivet,　the　shear　load　was　generally　greater　than　the　steel/steel　friction　interface.