The present invention discloses an information transmission method, a device, and a system, relates to the communications field, and resolves a problem in the prior art that in a D2D scenario, a terminal device cannot perform D2D communication due to a relatively long distance or a relatively significant change in channel quality. A specific solution is: generating, by a first device, a first scrambling sequence according to a first scrambling seed, where the first scrambling seed is generated according to a relay level or an information source of first information, scrambling the first information according to the first scrambling sequence, and sending the first information. The present invention is applied to information transmission.