Various embodiments provide a signal transmission method and apparatus, and is applied to a multi-band communications system. Under the method, a terminal reports bandwidth capability information of a first frequency band in a plurality of frequency bands to a radio access network node. An operating band of the terminal includes the first frequency band, the bandwidth capability information of the first frequency band indicates a bandwidth capability of the terminal in the first frequency band, the bandwidth capability in the first frequency band is not less than a first threshold, and the first threshold is determined based on a maximum bandwidth capability of the terminal, the first frequency band, or a subcarrier spacing of the first frequency band. The terminal can send or receive a signal on a resource allocated by the radio access network node based on the bandwidth capability information.