A congestion processing method, characterized in that, the method is applied to a core module of a data plane of a lossless transmission system which is implemented by a network device and comprises a control plane and the data plane and also a Fabric connecting the control plane and the data plane, wherein the control plane comprises a monitoring module and a management and control module, and the data plane comprises the core module and a forwarding module, wherein the monitoring module is used to cooperate with the core module to implement corresponding software functions, and takes a physical port in the network device as a unit, and a data flow sent by each physical port is mirrored to the core module in a round-robin manner for greedy flow identification, wherein the core module comprises software and hardware implementations and is used as an independent processing unit to be hung on the Fabric of the lossless transmission system, and the core module is adapted to: complete an identification of a greedy flow under high load on the forwarding plane, and store flow information of the greedy flow in a greedy flow table; monitor a congestion notification packet in a received data flow, analyze corresponding flow information, and query analyzed flow information in the greedy flow table; clear, if the query is unsuccessful, a congestion mark of the data packet; and keep, if the query is successful, the data packet unchanged; then query a forwarding table, and forward the data packet, wherein the management and control module is adapted to manage and control modules such as the monitoring module in the control plane, and manage and control modules such as the core module and the forwarding module in the data plane, wherein the forwarding module comprises multiple ports for forwarding data packets, and wherein the method comprises the steps of receiving, by the core module, a first data packet carrying a congestion mark through a target port; searching, by the core module, in a preset greedy flow table, a target table entry that includes target flow information carried in the first data packet and an identifier of the target port, and the preset greedy flow table stores flow information of a data flow whose traffic is greater than a preset traffic threshold and an identifier of a port that receives a data flow corresponding to the flow information; processing, by the core module, if the target table entry is found, the first data packet; removing, by the core module, if the target table entry is not found, the congestion mark carried in the first data packet to obtain a second data packet, and processing the second data packet. monitor a congestion notification packet in a received data flow, analyze corresponding flow information, and query analyzed flow information in the greedy flow table; clear, if the query is unsuccessful, a congestion mark of the data packet; and keep, if the query is successful, the data packet unchanged; then query a forwarding table, and forward the data packet, wherein the management and control module is adapted to manage and control modules such as the monitoring module in the control plane, and manage and control modules such as the core module and the forwarding module in the data plane, wherein the forwarding module comprises multiple ports for forwarding data packets, and wherein the method comprises the steps of receiving, by the core module, a first data packet carrying a congestion mark through a target port; searching, by the core module, in a preset greedy flow table, a target table entry that includes target flow information carried in the first data packet and an identifier of the target port, and the preset greedy flow table stores flow information of a data flow whose traffic is greater than a preset traffic threshold and an identifier of a port that receives a data flow corresponding to the flow information; processing, by the core module, if the target table entry is found, the first data packet; removing, by the core module, if the target table entry is not found, the congestion mark carried in the first data packet to obtain a second data packet, and processing the second data packet. receiving, by the core module, a first data packet carrying a congestion mark through a target port; searching, by the core module, in a preset greedy flow table, a target table entry that includes target flow information carried in the first data packet and an identifier of the target port, and the preset greedy flow table stores flow information of a data flow whose traffic is greater than a preset traffic threshold and an identifier of a port that receives a data flow corresponding to the flow information; processing, by the core module, if the target table entry is found, the first data packet; removing, by the core module, if the target table entry is not found, the congestion mark carried in the first data packet to obtain a second data packet, and processing the second data packet.