Embodiments of the present disclosure provide a method and a device for cross-domain strong logically isolation and secure access control in the Internet of Things (IoT). The method includes the following. When one IoT gateway receives the identity authentication request, the IoT gateway sends the identity authentication request to all IoT gateways in the domain excluding that IoT gateway. When all IoT gateways in the domain receive the identity authentication request, all IoT gateways verify separately whether the identity authentication request is legal. After a certain IoT gateway obtains the identity authentication result, a distributed consensus procedure is initiated. The IoT gateways in the domain reach a consensus on the identity authentication result through a distributed consensus mechanism, and the identity authentication result is written and stored to a block of a blockchain.