A configuration determination method and apparatus, a terminal device, and a network device are provided. The method includes the following operation. The terminal device determines to operate using a first configuration on a carrier combination corresponding to the first type of time domain unit, and/or to operate using the second configuration on the carrier combination corresponding to the second type of time domain unit. The carrier combination corresponding to the first type of time domain unit is configured with uplink subband(s), and the carrier combination corresponding to the second type of time domain unit is not configured with uplink subband(s). The first type of time domain unit includes a downlink time domain unit and/or a flexible time domain unit, and the second type of time domain unit includes a downlink time domain unit and/or a flexible time domain unit; and the carrier combination includes multiple carriers.