A method and an apparatus for monitoring bandwidth condition are provided. The method includes: determining a monitoring reference period of bandwidth data of a target domain name every preset monitoring interval duration; obtaining bandwidth-data average values of the target domain name in the monitoring reference period during a current statistical cycle and a plurality of historical statistical cycles; determining, according to the bandwidth-data average values and a preset confidence level, a bandwidth dynamic interval corresponding to the monitoring reference period; and monitoring, according to current bandwidth data of the target domain name and the bandwidth dynamic interval, a current bandwidth condition of the target domain name. Using the disclosed method and apparatus is able to detect abnormal bandwidth condition in time, which is conducive to repairing the abnormal condition before the service provider detects the bandwidth anomaly, and thus ensures the overall service quality of the client.