A communication beam determining method and a corresponding apparatus are disclosed. The method includes respectively sending, by a network side device, downlink sounding signals by using M beams with a first width, where main lobe directions of any two of the M beams are different; receiving, by the network side device, sounding results returned by user equipment (UE), and determining N beams with a second width based on the sounding results, where the second width is less than the first width, a coverage area of a set of the N beams is smaller than a coverage area of a set of the M beams, and M and N are integers and not less than 2; and respectively sending, by the network side device, downlink scanning signals by using the N beams, and determining, based on scanning results returned by the UE, a first beam for data transmission with the UE.