Embodiments of this application provide a buffer status report (BSR) sending method, a terminal device, and a network device. The method includes: determining a first resource configured for a first channel; adding, a first cyclic redundancy check (CRC) to a BSR; and sending a second channel on the first resource, or sending the first channel and a second channel on the first resource, where the second channel is used to carry the BSR to which the first CRC is added. Based on the embodiments of this application, the terminal device independently adds the first CRC to the BSR, and sends the second channel carrying the BSR to a network device, so that the network device learns arrival of data corresponding to the second channel at the terminal device. Therefore, the network device can pre-configure a resource for the data, thereby reducing a transmission latency of the data.