The present disclosure relates to the field of communications technologies, and provides a multi-stream transmission method and device in an SDN network. A server obtains network status information of a network by using an SDN controller; determines, according to the network status information and a data sending rate requirement of a client, a quantity of sub-streams and a sub-stream transmission path that are required by a multi-stream connection, and allocates corresponding sub-stream identification information to each sub-stream; and sends the determined sub-stream transmission path and the corresponding sub-stream identification information to the SDN controller. According to the foregoing solution, the server completes multi-stream connection path planning according to the network status information, and the SDN controller only provides the network status information for the server without performing the multi-stream connection path planning, so that calculation load of the SDN controller is reduced.