Embodiments of this application provide a data transmission method and a device. The method includes: obtaining, by a terminal, first indication information or second indication information, where the first indication information is used to indicate that a reference signal is carried in a resource unit, and the second indication information is used to indicate that no reference signal is carried in a resource unit; and performing, by the terminal, data transmission according to the first indication information or the second indication information. The reference signal can be properly configured in the embodiments.