Resistance　spot　welding　(RSW)　of　aluminium/steel　dissimilar　materials　has　important　application　prospects　in　industries　such　as　automobiles.　However,　the　relatively　poor　mechanical　properties　of　the　welds　due　to　the　issue　of　brittle　intermetallic　compounds　(IMCs)　at　the　welding　interface　has　been　the　major　concerned　by　the　welding　community.　A　novel　modified　RSW　process　that　utilizes　relatively　high-frequency　linear　actuator　embedded　in　the　electrode　is　proposed　and　experimentally　verified.　The　linear　actuator　superimposes　a　pulsed　electrode　force　to　base　force　which　is　expected　to　facilitate　the　melt　flow　inside　the　aluminium　nugget　and　modify　the　forming　process　of　the　IMCs.　The　experimental　results　demonstrate　that　the　introduction　of　linear　actuating　could　significantly　increase　the　area　of　the　aluminium　nugget,　which　means　more　aluminium　was　melted.　Further,　it　is　observed　that　the　thickness　of　the　IMCs　layer　was　reduced　by　81.9　%,　with　a　peak　thickness　of　1.48　mu　m.　Therefore,　38.5　%　improvement　in　the　average　peak　tensile　shear　load　of　the　welded　joints　was　achieved.　The　involved　mechanisms　were　discussed　by　thermal/force　dynamic　analysis.