The　application　of　lightweight　materials　in　automotive　industry　creates　the　demand　to　develop　reliable　and　cost-effective　solutions　for　joining　hybrid　material　parts　and　assemblies.　In　this　work,　the　microstructure　and　mechanical　properties　of　the　dissimilar　joint　between　aluminum　alloy　6061　(AA6061)　and　carbon　fiber-reinforced　polyphenylene　sulfide　(CF-PPS)　processed　by　refill　friction　stir　spot　welding　(RFSSW)　were　investigated.　The　results　show　that　the　joining　between　AA6061　and　CF-PPS　is　attributed　to　the　combined　effect　of　mechanical　interlocking　and　adhesive　bonding.　The　rotation　speed　affects　the　porosity　at　the　AA6061/CF-PPS　interface　which　is　the　governing　factor　of　the　joints＇　peak　load　during　the　lap-shear　test.　Varying　rotation　speed　from　1000　to　1400　rpm,　it　illustrated　that　the　lap-shear　joints　produced　under　1200　rpm　possess　the　highest　peak　load　of　1460　N.　Besides,　it　is　observed　that　the　joints　produced　with　1200　rpm　have　a　thicker　adhesive　layer,　which　possess　a　strong　mechanical　interlocking　effect.　The　failure　mechanism　for　the　joints　includes　cohesive　and　adhesive　fracturing.　Under　the　optimized　rotation　speed,　the　fracturing　surface　of　the　sample　possess　dimples　with　fiber　pull-outed　fibers,　which　infers　a　ductile　failure.