In view of the problem that mobile nodes lack trusted verification in Wireless Sensor Network (WSN), a mobile node access authentication protocol was proposed in Internet of Things (IoT). Mutual authentication and key agreement between the sensor nodes and mobile sink nodes were realized, when they wre authenticated. At the same time, the trustness of mobile node platform was authenticated by sensor nodes. The authentication scheme was based on trusted computing technology without using base station and its concrete steps were described in detail. Pseudonyms and the corresponding public/private keys were used in authentication to achieve the protection of the user privacy. The proposed scheme was provably secure in the CK (Canetti-Krawczyk) security model. Compared to similar mobile node schemes, the protocol is more suitable for fast authentication in IoT, with less computation and communication overhead.