A quality of service monitoring method performed by a first packet processing device, wherein the method comprises the steps of: • obtaining (S 605) an identifier of a service flow of a terminal, a first quality of service monitoring parameter of a first flow splitting link for transmitting the service flow and first flow splitting link correlation information of the first flow splitting link, and a second quality of service monitoring parameter of a second flow splitting link for transmitting the service flow and second flow splitting link correlation information of the second flow splitting link; ° generating monitoring packets which are specifically packets that are used to monitor quality of service, o wherein the first quality of service monitoring parameter comprises a monitoring packet sending period corresponding to the first flow splitting link, and the second quality of service monitoring parameter comprises a monitoring packet sending period corresponding to the second flow splitting link; • correlating (S606) the identifier of the service flow, the first quality of service monitoring parameter, and the first flow splitting link correlation information; and correlating the identifier of the service flow, the second quality of service monitoring parameter, and the second flow splitting link correlation information; • monitoring quality of service of the first flow splitting link based on the identifier of the service flow, the first quality of service monitoring parameter, and the first flow splitting link correlation information; or monitoring quality of service of the second flow splitting link based on the identifier of the service flow, the second quality of service monitoring parameter, and the second flow splitting link correlation information. • obtaining (S 605) an identifier of a service flow of a terminal, a first quality of service monitoring parameter of a first flow splitting link for transmitting the service flow and first flow splitting link correlation information of the first flow splitting link, and a second quality of service monitoring parameter of a second flow splitting link for transmitting the service flow and second flow splitting link correlation information of the second flow splitting link; ° generating monitoring packets which are specifically packets that are used to monitor quality of service, o wherein the first quality of service monitoring parameter comprises a monitoring packet sending period corresponding to the first flow splitting link, and the second quality of service monitoring parameter comprises a monitoring packet sending period corresponding to the second flow splitting link; ° generating monitoring packets which are specifically packets that are used to monitor quality of service, o wherein the first quality of service monitoring parameter comprises a monitoring packet sending period corresponding to the first flow splitting link, and • correlating (S606) the identifier of the service flow, the first quality of service monitoring parameter, and the first flow splitting link correlation information; and correlating the identifier of the service flow, the second quality of service monitoring parameter, and the second flow splitting link correlation information; • monitoring quality of service of the first flow splitting link based on the identifier of the service flow, the first quality of service monitoring parameter, and the first flow splitting link correlation information; or monitoring quality of service of the second flow splitting link based on the identifier of the service flow, the second quality of service monitoring parameter, and the second flow splitting link correlation information. <EOS>