General　quantum　key　agreement　(QKA)　protocols　require　each　participant　to　make　the　same　contribution　to　the　generation　of　a　shared　key,　but　this　situation　cannot　meet　the　needs　of　government　or　military　which　require　a　third　party　only　to　control　key　agreement　process.　This　paper　proposed　a　continuous-variable　quantum　key　agreement　(CVQKA)　protocol　with　multi-party　Greenberg-Horne-Zeilinger　(GHZ)　entangled　states　generated　by　a　third　party.　The　third　party　prepares　quantum　states　by　sending　multi-photon　beam　with　higher　emission　frequency　and　stronger　signal.　Taking　continuous　variable　as　carrier,　the　information　carried　by　each　carrier　increases,　which　improves　the　security　key　rate.　In　this　paper,　the　third　party　controls　but　does　not　contribute　to　the　final　key.　After　receiving　the　states,　each　participant　encodes　his　or　her　own　key,　adds　a　decoy　state　and　sends　it　to　the　next　participant,　until　receiving　the　quantum　state　that　was　encoded　by　all　the　participants.　Then,　participants　can　measure　and　calculate　to　get　the　final　shared　key.　It　shows　that　our　protocol　is　easy　to　implement　and　has　high　efficiency.　Security　analysis　shows　that　our　protocol　can　resist　collusion　attacks,　beam　splitter　attack,　etc.