The invention provides a priority scheduling method, comprising a plurality of steps that: step S302, different identification codes are set for at least two different businesses; step S304, a digital subscriber line accesses a multiplexer and captures packet in the downstream data flows by using a data message capture mechanism according to the identification code, the data packet with the identification code indicating a scheduled service is determined as the service data packet of the highest priority; step S306, the priority of the service data packet captured is modified, and the messageafter modifying the priority is forwarded; and step S308, when the downstream bandwidth is not free, the digital subscriber line accessing multiplexer carries out a corresponding hierarchical scheduling according to the priority of the data packet. Thus, a function of priority scheduling can be realized without the operator modifying the existing higher-level device.