Threshold　signature　has　security　and　robustness,　so　more　and　more　scholars　pay　close　attention　to　it.　Aiming　at　the　disadvantage　that　it　cannot　prevent　conspiracy　attack,　this　paper　makes　full　use　of　tracing　set　and　other　technologies,　proposes　a　threshold　signature　model　which　can　withstand　the　conspiracy　attack　and　resolves　conspiracy　attack　problem　successfully.　Moreover,　the　model　can　prevent　replay　attack,　has　forward　security　and　without　the　support　of　the　trusted　centre.　At　last,　this　paper　proves　that　in　the　standard　model,　the　model　is　unforgeable　under　adaptive　chosen　message　attack.　Copyright　©　2019　Inderscience　Enterprises　Ltd.