This　study　developed　a　prefabricated　square　reinforced　concrete-filled　steel　tubular　(PRCFST)　pier　with　a　grouting　sleeve　connection.　The　seismic　performance　of　the　developed　pier　is　investigated　by　quasi-static　testing　and　finite　element　analysis　(FEA).　A　restoring　force　model　for　the　PRCFST　pier　with　a　grouting　sleeve　connection　is　developed　to　predict　its　hysteretic　behaviour　and　provide　an　efficient　methodology　for　analyzing　its　seismic　response.　The　results　demonstrated　that　the　pier　exhibited　exceptional　seismic　performance　and　deformability.　Damage　to　the　PRCFST　pier　was　concentrated　at　the　interface　between　the　pier　column　and　foundation　slab,　indicating　that　the　connection　form　not　only　prevents　significant　damage　to　the　foundation　slab　but　also　delays　or　mitigates　local　buckling　of　the　steel　tube.　An　increase　in　the　axial　compression　ratio　significantly　reduced　the　ductility　coefficient　of　the　pier,　while　an　increase　in　the　width-to-thickness　ratio　significantly　enhanced　the　ductility　coefficient.　A　comparative　analysis　of　test　results　and　numerical　simulations　indicated　that　the　developed　restoring　force　model　accurately　predicted　the　hysteretic　behaviour　of　the　PRCFST　pier.　And　the　restoring　force　model　provides　valuable　theoretical　support　for　conducting　elastic-plastic　time-history　analysis　of　such　piers　under　seismic　loading.