Embodiments of the present invention provide a QoS control method and a device for SDN. A control plane device includes: a determining unit, configured to determine a flow entry, where the flow entry includes QoS information, the QoS information is used to indicate a QoS processing rule, the QoS processing rule includes a QoS parameter, and the QoS processing rule is used to instruct to perform QoS control on a data packet according to the QoS parameter; and a sending unit, configured to send the flow entry to a forwarding plane device, so that the forwarding plane device obtains the QoS processing rule, and performs QoS control on a target packet according to the QoS parameter in the QoS processing rule, where the target packet is a data packet that matches the flow entry.