The present disclosure provides an information transmission method, a device, and a system, and relates to the communications field, so as to resolve a prior-art problem that when an unlicensed spectrum is preempted to send data, a receive end cannot obtain a correct time resource sequence number, and cannot descramble information. A first device scrambles, according to a first scrambling code sequence, first data carried on a first time resource on an unlicensed carrier, where the first data is data that is sent by the first device to a second device, and the first scrambling code sequence is generated according to a sequence number of a second time resource on a licensed carrier or a first value; and the first device sends scrambled first data to the second device.