With　the　continuous　development　of　the　Internet　of　Things　technology,　the　security　of　the　Internet　of　Things　has　attracted　more　and　more　attention.　Terminal　equipment　access　authentication　is　an　important　link　to　ensure　the　security　of　the　Internet　of　Things.　The　current　centralized　authentication　architecture　has　risks　such　as　poor　scalability,　poor　flexibility,　and　single　point　of　failure.　In　addition,　traditional　access　authentication　schemes　mainly　rely　on　digital　certificates　for　identity　authentication,　which　has　the　problems　of　high　communication　overhead　and　cannot　adapt　to　the　Internet　of　Things　environment　with　limited　terminal　equipment　resources.　To　solve　these　problems,　this　paper　proposes　a　distributed　secure　access　scheme　for　IoT　based　on　blockchain　technology.