The invention discloses a power communication service flow classification control method and system based on a PTN (Packet Transport Network). The method includes the following steps: formulating a priority classification strategy and a service level strategy; obtaining a service data stream; conducting service classification on the service data stream; conducting priority marking on services according to a service classification result and the priority classification strategy; configuring corresponding QoS (Quality of Service) parameters for each service according to service levels; obtainingnetwork monitoring information; and distributing different bandwidths to the services on the basis of the network monitoring information and the QoS parameters and also controlling forwarding. The power communication service flow classification control method and system, solving problems such as a large amount of PTN network services, heavy workload of manual QoS configuration and complex maintenance, improves the bandwidth utilization rate of the PTN, improves the reliability and effectiveness of service transmission, and greatly improves the service forwarding efficiency.