The　widespread　adoption　of　fifth-generation　mobile　networks　has　spurred　the　rapid　advancement　of　mobile　edge　computing　(MEC).　By　decentralizing　computing　and　storage　resources　to　the　network　edge,　MEC　significantly　enhances　real-time　data　access　services　and　enables　efficient　processing　of　large-scale　dynamic　data　on　resource-limited　devices.　However,　MEC　faces　considerable　security　challenges,　particularly　in　cross-domain　service　environments,　where　every　device　poses　a　potential　security　threat.　To　address　this　issue,　this　paper　proposes　a　secure　cross-domain　authentication　scheme　based　on　a　threshold　signature　tailored　to　MEC＇s　multi-subdomain　nature.　The　proposed　scheme　employs　a　(t,n)　threshold　mechanism　to　bolster　system　resilience　and　security,　catering　to　large-scale,　dynamic,　and　decentralized　MEC　scenarios.　Additionally,　the　proposed　scheme　features　an　efficient　authorization　update　function　that　facilitates　the　revocation　of　malicious　nodes.　Security　analysis　confirmed　that　the　proposed　scheme　satisfies　unforgeability,　collusion　resistance,　non-repudiation　and　forward　security.　Theoretical　evaluation　and　experimental　simulation　verify　the　effectiveness　and　feasibility　of　the　proposed　scheme.　Compared　with　existing　schemes,　the　proposed　scheme　has　higher　computational　performance　while　implementing　secure　authorization　updates.