In　quantum　key　agreement　(QKA),　a　shared　key　is　established　among　two　or　more　parties　where　each　participant　equally　contributes　its　part　to　the　shared　key,　and　none　of　the　participants　can　determine　the　shared　key　alone.　Zhou　et　al.　(Electron　Lett　40(18):1149,　2004)　gave　the　first　QKA　protocol　based　on　quantum　teleportation　and　since　then　quite　a　few　variants　and　extensions　have　been　proposed.　However,　none　of　the　existing　protocols　are　device-independent,　i.e.,　all　of　them　assume　implicitly　that　the　single-photon　states　or　entangled　states　supplied　to　the　participants　are　of　certain　form.　In　this　work,　we　exploit　the　idea　of　the　device-independent　dimension　witness　for　independent　preparation　and　measurement　devices　proposed　by　Tavakoli　(Phys　Rev　Lett　125:15050,　2020)　and　connect　it　with　the　QKA　protocol　(Chong　and　Hwang　in　Opt　Commun　283:1192-1195,　2010)　to　present　the　concept　of　semi-device-independent　QKA　protocol　for　the　first　time.