Embodiments provide an information sending method, an information receiving method, a network device, and a terminal device, to enable the terminal device to determine a correct uplink transmission time, thereby avoiding an uplink transmission failure. For achieving this, a network device determines a first receiving start time and a first sending start time. The first receiving start time is a receiving time at which the network device starts to receive a signal in a first time period, and the first sending start time is a sending time at which the network device starts to send a signal in a second time period. The network device sends indication information to a terminal device to instruct the terminal device to determine a second sending start time. The second sending start time is determined based on the first receiving start time and the first sending start time.