This application provides an information transmission method and device. The method includes: determining, by a terminal device when an uplink-downlink configuration between the terminal device and a network device is a first uplink-downlink configuration, a first resource used to transmit first information; receiving, by the terminal device, indication information from the network device, where the indication information is used to indicate that the uplink-downlink configuration is a second uplink-downlink configuration; determining, by the terminal device based on the indication information, a second resource used to transmit the first information; and transmitting, by the terminal device, the first information with the network device on the second resource.