Disclosed are a beam training method and device, and a communication system, used for reducing the overheads of a beam training process between a transmitting end and a receiving end. The present application provides a beam training method, the method comprising: a transmitting end determining a first mapping relationship between BPL identifiers and transmission beams; the transmitting end configuring a first reference signal resource for a receiving end, and transmitting configuration information concerning the first reference signal resource to the receiving end, the configuration information carrying a first BPL identifier.