Embodiments of the present disclosure provide an aperiodic SRS transmission method and an apparatus, and relate to the communications field, so as to resolve a problem that an existing terminal device cannot send an aperiodic SRS on a carrier of an unlicensed spectrum. The transmission method includes: obtaining, by a terminal device, first indication information, where the first indication information is used to instruct the terminal device to send an aperiodic sounding reference signal SRS on a first symbol in a first subframe; and sending, by the terminal device, the aperiodic SRS on the first symbol based on the first indication information.