A data transmission method in an enhanced CELL_FACH state, a network system, and a corresponding device are provided. The method includes the following steps. A radio transceiver receives information indicating a capability category of a UE. The radio transceiver acquires the capability category of the UE according to the information indicating the capability category of the UE. The radio transceiver performs data transmission to or from the UE according to the capability category of the UE. Since the information indicating the capability category of the UE is sent to the radio transceiver during the enhanced CELL_FACH data transmission, the radio transceiver performs the data transmission based on the capability category of a target UE, instead of the lowest capability category of the UE, thereby increasing the data transmission rate in the enhanced CELL_FACH state.