A domain name bandwidth adjustment method applied to a CDN system and applied at an edge node server or a relay node server in the CDN system, characterized in that, the method comprises: determining whether the CDN system triggers a bandwidth speed limiting policy, if yes, determining a to-be-limited target domain name from domain names served by the CDN system, and performing the bandwidth speed limiting policy on the target domain name; and when the bandwidth speed limiting policy is being executed, determining an initial reference bandwidth of the target domain name, and comparing the initial reference bandwidth with an actual bandwidth of the target domain name within a specified observation duration, to determine whether to perform step adjustment on the initial reference bandwidth and determine whether to release the bandwidth speed limiting policy; when a duration of time-in which the actual bandwidth of the target domain name is less than or equal to a proportion reference bandwidth-reaches a preset reference duration, performing step adjustment on the initial reference bandwidth of the target domain name; wherein the performing step adjustment on the initial reference bandwidth comprises: determining an adjusted step reference bandwidth according to the initial reference bandwidth and a preset growth coefficient, and recording a time node at which the bandwidth is adjusted; determining, from the time node at which the bandwidth is adjusted, whether a duration of time-in which the actual bandwidth of the target domain name is less than or equal to the proportion reference bandwidth-reaches the preset reference duration; and if the duration of time reaches the preset reference duration, determining a new step reference bandwidth according to the step reference bandwidth and the preset growth coefficient, and recording a time node at which the bandwidth is adjusted. determining whether the CDN system triggers a bandwidth speed limiting policy, if yes, determining a to-be-limited target domain name from domain names served by the CDN system, and performing the bandwidth speed limiting policy on the target domain name; and when the bandwidth speed limiting policy is being executed, determining an initial reference bandwidth of the target domain name, and comparing the initial reference bandwidth with an actual bandwidth of the target domain name within a specified observation duration, to determine whether to perform step adjustment on the initial reference bandwidth and determine whether to release the bandwidth speed limiting policy; when a duration of time-in which the actual bandwidth of the target domain name is less than or equal to a proportion reference bandwidth-reaches a preset reference duration, performing step adjustment on the initial reference bandwidth of the target domain name; wherein the performing step adjustment on the initial reference bandwidth comprises: determining an adjusted step reference bandwidth according to the initial reference bandwidth and a preset growth coefficient, and recording a time node at which the bandwidth is adjusted; determining, from the time node at which the bandwidth is adjusted, whether a duration of time-in which the actual bandwidth of the target domain name is less than or equal to the proportion reference bandwidth-reaches the preset reference duration; and if the duration of time reaches the preset reference duration, determining a new step reference bandwidth according to the step reference bandwidth and the preset growth coefficient, and recording a time node at which the bandwidth is adjusted. determining an adjusted step reference bandwidth according to the initial reference bandwidth and a preset growth coefficient, and recording a time node at which the bandwidth is adjusted; determining, from the time node at which the bandwidth is adjusted, whether a duration of time-in which the actual bandwidth of the target domain name is less than or equal to the proportion reference bandwidth-reaches the preset reference duration; and if the duration of time reaches the preset reference duration, determining a new step reference bandwidth according to the step reference bandwidth and the preset growth coefficient, and recording a time node at which the bandwidth is adjusted.