Two　multiparty　simultaneous　quantum　identity　authentication　(MSQIA)　protocols　based　on　secret　sharing　are　presented.　All　the　users　can　be　authenticated　by　a　trusted　third　party　(TTP)　simultaneously.　In　the　first　protocol,　the　TTP　shares　a　random　key　K　with　all　the　users　using　quantum　secret　sharing.　The　ith　share　acts　as　the　authentication　key　of　the　ith　user.　When　it　is　necessary　to　perform　MSQIA,　the　TTP　generates　a　random　number　R　secretly　and　sends　a　sequence　of　single　photons　encoded　with　K　and　R　to　all　the　users.　According　to　his　share,　each　user　performs　the　corresponding　unitary　operations　on　the　single　photon　sequence　sequentially.　At　last,　the　TTP　can　judge　whether　the　impersonator　exists.　The　second　protocol　is　a　modified　version　with　a　circular　structure.　The　two　protocols　can　be　efficiently　used　for　MSQIA　in　a　network.　They　are　feasible　with　current　technology.