Aiming at information exchange requirements of cross-trust domains under IoT scenario, this paper constructs an authentication architecture which suits for IoT with blockchain and edge computing. Firstly, based on consortium chain, the paper designs architecture and process for cross-domain authentication in IoT, creates secure cross-domain information exchange environment for IoT. In addition, edge gateway is introduced to shield heterogeneity and sensitive information of things. Based on edge gateway,authentication protocol for cross-trust domain authentication is designed, which strengthens privacy preserving in IoT. Finally,performance analysis proves that the design could resist common attacks in IoT scenario. Simulation results prove that the design has better performance than traditional way in both computation consumption and communication consumption, can be used for IoT.