An uplink transmission method and a communications apparatus, the method including when transmitting, in a subframe in which an autonomous uplink transmission resource is configured, uplink data by using a first hybrid automatic repeat request (HARQ) process, considering that a new data indicator (NDI) for the first HARQ process is toggled, where the first HARQ process is a HARQ process that can be used for autonomous uplink transmission, and before the subframe, there is no uplink grant for the first HARQ process delivered to a HARQ entity, and performing new uplink data transmission in the subframe by using the first HARQ process.