The　combination　of　edge　computing　(EC)　and　the　Internet　of　Things　is　a　hot　research　topic.　And　security　is　one　of　the　most　important　problems　to　be　solved.　The　trust　measurement　of　devices　is　an　effective　way　to　solve　the　security　problem,　and　the　lack　of　a　unified　trust　measurement　model　makes　the　untrusted　devices　destroy　the　quality　of　service.　Establishing　a　reliable　trust　relationship　between　devices　can　effectively　improve　the　security　of　the　system.　A　decentralized　trust　measurement　model　for　devices　is　proposed.　First,　a　decentralized　trust　measurement　framework　is　proposed,　which　combines　EC　with　blockchain　technology　to　establish　a　decentralized　hierarchical　structure;　second,　the　credibility　of　devices　is　measured　from　multilevel　and　multi-attribute;　finally,　a　feedback　trust　filtering　mechanism　is　designed　to　filter　reliable　feedback　information,　and　then　the　trust　between　devices　and　the　comprehensive　trust　of　devices　are　calculated.　Experiments　and　analysis　show　that　the　proposed　decentralized　trust　measurement　model　can　effectively　measure　the　trust　degree　of　devices　and　resist　various　malicious　feedback　attacks.