A　multiparty　simultaneous　quantum　identity　authentication　protocol　based　on　Greenberger-Horne-Zeilinger　(GHZ)　states　is　proposed.　The　multi-user　can　be　authenticated　by　a　trusted　third　party　(TTP)　simultaneously.　Compared　with　the　scheme　proposed　recently　(Wang　et　al　2006　Chin.　Phys.　Lett.　23(9)　2360),　the　proposed　scheme　has　the　advantages　of　consuming　fewer　quantum　and　classical　resources　and　lessening　the　difficulty　and　intensity　of　necessary　operations.