A method and device for transmitting data, which are used for solving the problems in the prior art that an existing frame structure would increase the user-plane delay of a TD-LTE system and decrease the system performance. A wireless frame transmitted between a network side device and a terminal comprises a reinforced sub-frame, and the reinforced sub-frame comprises a UL portion and a DL portion. A TDD frame structure of the embodiments of the present invention can decrease the user-plane delay on the basis of maintaining the service flexibility, and also can maintain the backward compatibility of a system.