The present application discloses a congestion control method and an apparatus. The method includes: receiving, by a root node network element, a first link notification message; determining, based on the link status information of the first link, that the first link is congested; determining an identifier of a first leaf node network element based on a correspondence between an identifier of the first port and the identifier of the first leaf node network element; determining a service queue of the first leaf node network element based on a correspondence between the identifier of the first leaf node network element and an identifier of the service queue of the first leaf node network element; and lowering output bandwidth of the service queue of the first leaf node network element.