A　quantum　deniable　authentication　protocol　based　on　the　theory　of　continuous　quantum　by　using　two-mode　squeezed　quantum　states　is　proposed.　By　introducing　the　key　agreement　mechanism,　the　message　sender　and　the　specified　receiver　will　first　agree　a　new　shared　secret　key　by　key　update　phases　without　the　help　of　a　third　center　and　without　their　interaction　by　utilizing　the　amplitude　and　the　phase　properties　of　the　entangled　optical　modes,　and　then　the　sender　generates　the　message　authentication　code　by　using　the　new　shared　secret　key.　Security　analysis　results　show　that　the　protocol　satisfies　the　basic　security　requirements　of　deniable　authentication　protocol　such　as　completeness　and　deniability,　and　can　withstand　forgery　attack,　impersonation　attack,　inter-resend　attack　and　beam　splitter　attack.　©　2020　Elsevier　GmbH