A method for data transmission in a sidelink includes: a first terminal device selecting a first resource from a data resource pool in a selection window, the first resource being used for sending data of the first terminal device; the first terminal device selecting, from a control resource pool in the selection window, a second resource for sending first indication information, the first indication information being used for indicating the first resource, the positions of the first resource and the second resource in a time domain and/or frequency domain being different; and the first terminal device sending the first indication information over the second resource, and sending the data of the first terminal device over the first resource.