Abstract: The present disclosure provides a load balancing method, device and system. In some embodiments, in response to a first connection establishing message, which is configured to establish a main connection of a MPTCP session and sent by a client device via a first network interface, first token information of the main connection is generated; a corresponding relation between the first token information and a server device that receives the first connection establishing message is added into a preset first connection forwarding table; and in response to a second connection establishing message, which is configured to establish a sub-connection of the MPTCP session and sent by the client device via a second network interface, the second connection establishing message is sent to the server device corresponding to a second token information in the second connection establishing message. The second token information is the first token information of the main connection to which the sub-connection belongs.