An information transmission method, comprising: determining (S202a), by a user equipment, a channel corresponding to the user equipment within an IEEE 802.11 announcement transmission interval, ATI; receiving, by the user equipment on the channel corresponding to the user equipment within the ATI, a request frame sent by a network device, wherein the request frame comprises frame length indication information; and sending, by the user equipment based on the frame length indication information, a first response frame to the network device on the channel corresponding to the user equipment within the ATI, wherein a length of the first response frame is a frame length corresponding to the frame length indication information; characterized in that before the sending, by the user equipment based on the frame length indication information, a first response frame to the network device on the channel corresponding to the user equipment within the ATI, the method further comprises: comparing, by the user equipment, a length of a to-be-sent second response frame with the frame length corresponding to the frame length indication information; and if the length of the second response frame is less than the frame length corresponding to the frame length indication information, adding, by the user equipment, padding information to the second response frame to obtain the first response frame, so that the length of the first response frame is the frame length corresponding to the frame length indication information. determining (S202a), by a user equipment, a channel corresponding to the user equipment within an IEEE 802.11 announcement transmission interval, ATI; receiving, by the user equipment on the channel corresponding to the user equipment within the ATI, a request frame sent by a network device, wherein the request frame comprises frame length indication information; and sending, by the user equipment based on the frame length indication information, a first response frame to the network device on the channel corresponding to the user equipment within the ATI, wherein a length of the first response frame is a frame length corresponding to the frame length indication information; characterized in that before the sending, by the user equipment based on the frame length indication information, a first response frame to the network device on the channel corresponding to the user equipment within the ATI, the method further comprises: comparing, by the user equipment, a length of a to-be-sent second response frame with the frame length corresponding to the frame length indication information; and if the length of the second response frame is less than the frame length corresponding to the frame length indication information, adding, by the user equipment, padding information to the second response frame to obtain the first response frame, so that the length of the first response frame is the frame length corresponding to the frame length indication information. comparing, by the user equipment, a length of a to-be-sent second response frame with the frame length corresponding to the frame length indication information; and if the length of the second response frame is less than the frame length corresponding to the frame length indication information, adding, by the user equipment, padding information to the second response frame to obtain the first response frame, so that the length of the first response frame is the frame length corresponding to the frame length indication information.