A packet processing method includes receiving, by a forwarding apparatus, a first packet, where the first packet belongs to a first packet flow, determining, by the forwarding apparatus, at least two types of information in the following four types of information a duration of staying in a first memory by the first packet flow, usage of the first memory, whether the first packet flow is a victim of a congestion control mechanism, and a drop priority of the first packet, and determining, by the forwarding apparatus based on the at least two types of information, whether explicit congestion notification marking needs to be performed on the first packet.