Embodiments of the present application provide a data transmission method, a device, and a system, and relate to the communications field, to reduce signaling exchanges between an access network device and a UE, thereby saving network resources and improving data transmission efficiency. The data transmission method includes: receiving, by a user equipment UE, a scrambled control channel; descrambling, by the UE, the scrambled control channel by using a first identifier, to obtain control information and cyclic redundancy code CRC; and after the UE completes a check on the CRC, receiving, by the UE according to the control information, data sent by an access network device.