A data transmission method includes obtaining, by user equipment (UE), a maximum transmit power; determining, by the UE, a transmit power of a data channel and/or a transmit power of a control channel based on the maximum transmit power and a first parameter, where the first parameter includes at least one of the following: a bandwidth of the data channel, a bandwidth of the control channel, or a carrier type of a carrier of a first link; and sending, by the UE, the control channel and the data channel in a same subframe.