The　Internet　of　Things　(IoT)　is　a　vast　perceptual　network　formed　by　a　variety　of　IoT　devices　connected　to　each　other.　In　IoT,　various　devices　cooperate　with　each　other　to　collect　and　transmit　private　data　of　loT　and　sustain　the　efficient　and　orderly　operation　of　IoT.　However,　in　the　complex　security　situation　of　IoT,　due　to　the　resources　of　IoT　devices　being　limited,　it　is　difficult　for　IoT　devices　to　afford　the　heavy　resource　consumption　of　sophisticated　data　encryption　and　decryption　mechanism,　which　brings　certain　security　risk　to　data　transmission　of　IoT.　To　ensure　safe　and　efficient　data　transmission,　we　propose　an　improved　efficient　certificateless　hybrid　signcryption　scheme　for　IoT,　which　satisfies　confidentiality,　unforgeability,　forward　security,　public　verification,　and　known　session-specific　temporary　information　security;　meanwhile,　we　prove　them　in　random　oracle　model　(ROM).　In　addition,　through　simulation　experiment,　we　find　that　our　scheme　has　higher　communication　efficiency　and　computational　efficiency　compared　with　existing　schemes.