The present disclosure provides a method and related devices for domain name bandwidth adjustment. The method includes: receiving domain name bandwidth information reported by each on-site bandwidth management server and based on the domain name bandwidth information, determining a target domain name having the domain name bandwidth exceeding a specified bandwidth threshold; determining a to-be-adjusted bandwidth corresponding to the target domain name, and allocating the to-be-adjusted bandwidth among a plurality of sites; determining a bandwidth control threshold of the target domain name for the corresponding site; and generating a flow control instruction containing the bandwidth control threshold, and sending the generated flow control instruction to the on-site bandwidth management server at the corresponding site, where the on-site bandwidth management server adjusts the domain name bandwidth of the target domain name in each node server at the site.