A method, a device, and a system for performing balance adjustment on egress traffic of an SDN-based IDC network are disclosed, to resolve a technical problem that balance adjustment cannot be performed on egress traffic of an IDC network. The method includes: sending group information of at least one AS group to an SDN controller, where the group information is used by the SDN controller to generate an AS filtering policy and deliver the AS filtering policy to a DPE; obtaining AS traffic information that is obtained by the DPE through statistics collection according to the AS filtering policy; generating a traffic adjustment policy according to the AS traffic information, where the traffic adjustment policy is used to instruct to adjust traffic of a destination AS group to a destination egress link; and sending the traffic adjustment policy to the SDN controller.