Example packet control methods and apparatus are described. One example method includes detecting, by a network node, a packet in a packet flow causing a congestion from an upstream node. The network node reduces a scheduling priority of the packet in the packet flow and generates a congestion isolation message, where the congestion isolation message includes description information of the packet flow. The congestion isolation message is sent to the upstream node to instruct the upstream node to reduce the scheduling priority of the packet in the packet flow.