A system for controlling mutual access of smart devices, comprising a cloud server, wherein the cloud server comprises: an information processing module, configured to maintain Transmission Control Protocol long connections between smart devices and the cloud server, maintain connection sessions between the smart devices, and forward interaction data packets between the smart devices; an account and device management module, configured to manage registration of a unique home account, and add smart devices and device information corresponding to the smart devices to a device list under the home account; and a storage module, connected to the account and device management module and the information processing module, and configured to store the registered home account, the device list under the home account, the smart devices and the device information corresponding to the smart devices; and a permission management module, connected to the storage module, and configured to set access permission information corresponding to each of the smart devices; wherein the information processing module comprises: an authenticating unit, configured to authenticate legality of the home account and a smart device, wherein the home account and the smart device are authenticated as legal, if the home account and a password are authenticated by using the cloud server, and at the same time, if it is authenticated whether an ID of the smart device exists in the device list; a connection, session management and forwarding unit, configured to maintain the TCP long connections between the smart devices and the cloud server, maintain the connection sessions between the smart devices, and forward the interaction data packets between the smart devices, wherein a TCP long connection to the cloud server is established after the authentication succeeds for each of the smart devices; a unit for determining whether a device is online, configured to determine whether the smart device is online; and a permission determining unit, configured to determine whether the smart device has a corresponding access permission. an information processing module, configured to maintain Transmission Control Protocol long connections between smart devices and the cloud server, maintain connection sessions between the smart devices, and forward interaction data packets between the smart devices; an account and device management module, configured to manage registration of a unique home account, and add smart devices and device information corresponding to the smart devices to a device list under the home account; and a storage module, connected to the account and device management module and the information processing module, and configured to store the registered home account, the device list under the home account, the smart devices and the device information corresponding to the smart devices; and a permission management module, connected to the storage module, and configured to set access permission information corresponding to each of the smart devices; wherein the information processing module comprises: an authenticating unit, configured to authenticate legality of the home account and a smart device, wherein the home account and the smart device are authenticated as legal, if the home account and a password are authenticated by using the cloud server, and at the same time, if it is authenticated whether an ID of the smart device exists in the device list; a connection, session management and forwarding unit, configured to maintain the TCP long connections between the smart devices and the cloud server, maintain the connection sessions between the smart devices, and forward the interaction data packets between the smart devices, wherein a TCP long connection to the cloud server is established after the authentication succeeds for each of the smart devices; a unit for determining whether a device is online, configured to determine whether the smart device is online; and a permission determining unit, configured to determine whether the smart device has a corresponding access permission. an authenticating unit, configured to authenticate legality of the home account and a smart device, wherein the home account and the smart device are authenticated as legal, if the home account and a password are authenticated by using the cloud server, and at the same time, if it is authenticated whether an ID of the smart device exists in the device list; a connection, session management and forwarding unit, configured to maintain the TCP long connections between the smart devices and the cloud server, maintain the connection sessions between the smart devices, and forward the interaction data packets between the smart devices, wherein a TCP long connection to the cloud server is established after the authentication succeeds for each of the smart devices; a unit for determining whether a device is online, configured to determine whether the smart device is online; and a permission determining unit, configured to determine whether the smart device has a corresponding access permission.