A service traffic adjustment method, wherein the method comprises: obtaining, by a first controller, a first limit value of a traffic parameter and a second limit value of the traffic parameter, wherein the traffic parameter is a parameter of traffic corresponding to a service flow sent from a transmit end to a receive end and includes a service traffic rate and a burst volume; obtaining, by the first controller, a target value of the traffic parameter based on the first limit value, the second limit value, and configuration information of a forwarding device through which the service flow passes, wherein the configuration information of the forwarding device comprises a transmission rate of a port of the forwarding device, wherein the target value meets a delay requirement of the service flow, the target value falls within a range determined based on the first limit value and the second limit value, and the first limit value is not equal to the second limit value; and sending, by the first controller, the target value, wherein the target value is used to adjust the traffic of the service flow sent by the transmit end, wherein the obtaining, by the first controller, a target value of the traffic parameter based on the first limit value, the second limit value, and configuration information of a forwarding device through which the service flow passes comprises: obtaining, by the first controller, a first value of the traffic parameter based on the first limit value and the second limit value, wherein the first value falls within the range determined based on the first limit value and the second limit value; obtaining, by the first controller, a delay upper bound of the service flow from the transmit end to a receive end based on the first value and the configuration information of the forwarding device through which the service flow passes; and determining, by the first controller, the first value as the target value when the delay upper bound does not exceed a preset delay. obtaining, by a first controller, a first limit value of a traffic parameter and a second limit value of the traffic parameter, wherein the traffic parameter is a parameter of traffic corresponding to a service flow sent from a transmit end to a receive end and includes a service traffic rate and a burst volume; obtaining, by the first controller, a target value of the traffic parameter based on the first limit value, the second limit value, and configuration information of a forwarding device through which the service flow passes, wherein the configuration information of the forwarding device comprises a transmission rate of a port of the forwarding device, wherein the target value meets a delay requirement of the service flow, the target value falls within a range determined based on the first limit value and the second limit value, and the first limit value is not equal to the second limit value; and sending, by the first controller, the target value, wherein the target value is used to adjust the traffic of the service flow sent by the transmit end, wherein the obtaining, by the first controller, a target value of the traffic parameter based on the first limit value, the second limit value, and configuration information of a forwarding device through which the service flow passes comprises: obtaining, by the first controller, a first value of the traffic parameter based on the first limit value and the second limit value, wherein the first value falls within the range determined based on the first limit value and the second limit value; obtaining, by the first controller, a delay upper bound of the service flow from the transmit end to a receive end based on the first value and the configuration information of the forwarding device through which the service flow passes; and determining, by the first controller, the first value as the target value when the delay upper bound does not exceed a preset delay. obtaining, by the first controller, a first value of the traffic parameter based on the first limit value and the second limit value, wherein the first value falls within the range determined based on the first limit value and the second limit value; obtaining, by the first controller, a delay upper bound of the service flow from the transmit end to a receive end based on the first value and the configuration information of the forwarding device through which the service flow passes; and determining, by the first controller, the first value as the target value when the delay upper bound does not exceed a preset delay.