The　focus　of　this　paper　is　to　propose　an　efficient　and　secure　solution　dealing　with　the　key　escrow　problem　in　ID-based　signature　schemes,　i.e.,　the　Key　Generation　Manager　(KGM)　knows　the　user＇s　private　key.　In　this　paper,　we　describe　a　new　identity-based　threshold　signature　scheme.　Partial　signatures　can　be　expediently　generated　by　player　under　the　discrete　logarithm　problem.　Any　public　verifier　can　check　the　validity　of　partial　signatures　and　the　threshold　signature　by　verification　equations.　Through　the　analysis　of　security　and　efficiency　of　the　scheme,　we　show　that　our　scheme　is　both　unforgeable　and　(t,　n)-robust,　and　it　is　more　efficient　compared　with　the　previous　schemes.　©2007　IEEE.