Embodiments of this application provide a data scheduling method, an apparatus, and a system, to improve resource allocation flexibility when one piece of DCI schedules a plurality of TBs. A network device sends, to a terminal device, DCI used to schedule N TBs. After determining that a downlink channel that carries first M TBs in the N TBs is transmitted in consecutive first downlink time units, the network device sends the downlink channel carrying the M TBs to the terminal device in the first downlink time units. The terminal device receives the downlink channel carrying the M TBs. After determining that ACKs/NACKs corresponding to the M TBs are transmitted in consecutive first uplink time units, the terminal device sends the ACKs/NACKs corresponding to the M TBs to the network device in the first uplink time units. A start time of the first downlink time units is determined based on an end time of transmission of the DCI and a first delay, and a start time of the first uplink time units is determined based on an end time of the first downlink time units and a second delay.