According to a data transmission method, device and system provided in the embodiments of the present disclosure, a scheduling node sends, in a first TTI to a scheduled node, a scheduling indication of transmitting data by using a preset spectrum resource; after the scheduled node receives the scheduling indication, when it is determined that data can be transmitted in the second TTI according to the scheduling indication, data is transmitted; and when the scheduling node determines that the scheduled node can transmit data in the second TTI, it is determined that the data that is transmitted in the second TTI by using the preset spectrum resource is data sent by the scheduled node. A power loss of the scheduled node is reduced, waste of a wireless communications resource is reduced, and transmission efficiency is improved. The present disclosure relates to the field of communications technologies.