In an information transmission method, a receiving device receives a data frame from a sending device. The data frame occupies a transmission resource block, and includes RU allocation information. The receiving device determines indication information based on a location of a 160 MHz channel with more data tones of the transmission resource block and a resource block size indicated by the RU allocation information. The receiving device then determines a response resource block based on the indication information and the RU allocation information, and sends an acknowledgment frame for the data frame to the sending device on the response resource block.