In　smart　city,　technologies　such　as　blockchain,　Internet　of　Things　(IoT)　and　edge　computing　tend　to　be　integrated　that　promotes　horizontal　information　exchange　and　multi-party　cooperation.　Large　amounts　of　superior　services　can　be　provided　by　analyzing　the　information.　However,　lots　of　IoT　devices　generating　the　information　do　not　have　sufficient　resources　to　resist　malicious　attacks　so　that　the　devices　deliberately　upload　the　tampered　data,　which　reduces　quality　of　service.　To　solve　the　problem,　we　propose　a　data　source　trusted　proof　mechanism　based　on　the　node　security　measurement　and　threshold　ring　signature　method.　The　mechanism　firstly　judges　whether　a　node　is　in　a　trusted　domain　based　on　the　proposed　Distributed　Sub-domain　Networking　(DSN)　method　to　reduce　energy　consumption　and　avoid　single　point　failure.　Then,　it　quantifies　security　value　of　the　nodes　in　the　trusted　domain　based　on　the　proposed　three-dimension　security　measurement　method.　Finally,　it　confirms　authenticity　of　the　nodes　using　the　Chinese　Remainder　Theorem　(CRT)-based　threshold　ring　signature　scheme.Simulation　results　show　our　proposed　mechanism　can　distinguish　all　malicious　nodes　among　trusted　nodes,　the　loss　rate　of　trusted　nodes　is　reduced　to　less　than　5%　and　the　false　report　rate　reduced　to　less　than　10%.　(c)　2021　Elsevier　B.V.　All　rights　reserved