This application provides a congestion control method and a network device. The method includes: receiving a first message sent by a second network device, where the first message carries an active flow quantity, and the active flow quantity is a quantity determined by the second network device based on a data flow to which data packets received from a first network device belong; determining, based on the active flow quantity and rated receiving bandwidth of the second network device, packet sending control information used to send the data flow to the second network device; and sending the data flow to the second network device based on the packet sending control information. This application can better control congestion, thereby reducing network packet loss.