Most　of　the　existing　centralized　data　service　platforms　of　Internet　of　Things(IoT),　such　as　Geological　Big　Data　Sharing　and　Application　Platform　and　TalkingData　exacerbate　security　risks,　including　the　lack　of　a　standard　reputation　evaluation　system,　user　privacy　disclosure　and　vulnerability　to　data　tampering.To　address　the　problem,　a　blockchain-based　model　is　designed　and　implemented　to　evaluate　the　reputation　of　data　services.The　model　employs　the　Analytic　Hierarchy　Process(AHP)　to　calculate　the　weight　of　reputation　evaluation　indexes.Then　smart　contract　and　Interplanetary　File　System(IPFS)　are　used　to　realize　the　storage,　verification,　protection　and　sharing　of　IoT　data.At　the　same　time,　blockchain　and　Redis　are　used　to　realize　safe　and　fast　retrieval　and　storage　of　IoT　data　and　reputation　data.　Ring　signature　technology　is　also　used　to　ensure　the　authenticity　of　the　evaluation　and　hide　the　user　personal　information.The　test　results　show　that　the　model　is　decentralized,　reliable,　secure,　efficient　and　tamper-resistant.It　can　meet　the　reputation　evalution　requirements　of　the　data　service　platforms　of　IoT.　©　2022,　Editorial　Office　of　Computer　Engineering.　All　rights　reserved.