A data transmission method, a device and a system are disclosed. In an embodiment the data method includes obtaining, by UE, first information, where the first information includes at least one of a location information of the UE, a channel quality between the UE and a base station, a channel load between the UE and the base station, a size of data to be sent by the UE, or an uplink service arrival sparseness degree of the base station, determining, by the UE, whether the first information meets a preset condition, and, when the first information does not meet the preset condition, obtaining, by the UE, an unscheduled uplink data transmission resource, and sending data to the base station by using the unscheduled uplink data transmission resource.