The present invention discloses an information transmission method, a device, and a system, and relates to the communications field, so as to resolve a problem that a receiving device has excessively large power consumption because the receiving device needs to continuously perform blind detection on a channel to determine a moment at which data transmission is started. A specific solution is: obtaining, by a network device, a start location of a first subframe, configuring a first field in downlink control information DCI of a second subframe, and sending, to user equipment, the first subframe and the second subframe that are adjacent to each other, where the first field is used to indicate the start location of the first subframe. The present invention is used for information transmission.