This　study　reports　a　surface-enhanced　electrochemiluminescence　(SEECL)　sensor　for　the　ultrasensitive　detection　of　prostate-specific　antigen　(PSA)　in　human　serum.　First,　we　prepared　the　Au-SiO2　core-shell　nanocomposites　doped　with　Ru(bpy)32+　(Au@SiO2-Ru)　as　the　ECL　signal　generation　and　amplification　element　of　the　SEECL　sensor.　Ru(bpy)32+　could　emit　ECL　under　the　excitation　of　an　electrochemical　reaction,　and　generate　the　local　surface　plasmon　resonance　(LSPR)　electromagnetic　field　from　the　gold　nanoparticle　(AuNP)　core.　The　produced　LSPR　then　effectively　enhanced　the　ECL　signals.　This　sensing　strategy　was　utilized　for　the　detection　of　PSA,　which　can　be　absorbed　on　the　electrode　surface　by　the　reaction　between　PSA　and　monoclonal　antibodies.　When　polyclonal　antibody-modified　Au@SiO2-Ru　was　added,　the　PSA-double-antibody　sandwich　structure　was　formed　on　the　electrode　surface　and　thus,　the　Au@SiO2-Ru　were　quantitatively　immobilized　on　the　electrode　surface.　The　results　show　that　this　kind　of　SEECL　sensor　has　good　selectivity　toward　PSA.　Notably,　the　minimum　detection　concentration　reached　7　×　10-7　ng　mL-1　under　the　optimum　experimental　conditions,　which　is　much　better　than　most　of　the　previously　reported　approaches　for　the　detection　of　PSA　in　serum.　©　The　Royal　Society　of　Chemistry.