The invention relates to a broadcast channel-based file transmission method. The broadcast channel-based file transmission method includes the step that when a requested file is requested again in a transmission process, a file source server notifies a requestor to receive the file in a broadcast channel on which the file is being transmitted, and at the same time, the file source server re-starts a new broadcast channel on which the content of a remaining part that has been not transmitted on the previous broadcast channel is transmitted. As for file requests which are not arrived at the same time, the broadcast channel-based file transmission method of the invention can improve the reuse rate of broadcast channels, and requirements for server outlet bandwidth and HFC network bandwidth can be lowered.