A data transmission method and device, then method including obtaining, by a terminal device, a first resource and a second resource, where at least one first uplink transmission opportunity is configured for the first resource, a second uplink transmission opportunity is configured for the second resource, the first uplink transmission opportunity comprises X repeated first uplink transmission resources, the second uplink transmission opportunity comprises Y repeated second uplink transmission resources, and both X and Y are each integers greater than or equal to 1, and sending, by the terminal device, uplink data to a network device using the second uplink transmission opportunity in response to sending using N closest first uplink transmission opportunities before the second uplink transmission opportunity being blocked, where N is an integer greater than or equal to 1