Embodiments of the present invention provide a method and device for transmitting data. The method includes: determining, after receiving a first message sent by a user equipment, whether first indication information is set, where the first indication information indicates that a server buffers downlink data to be sent to the user equipment; and when determining that the first indication information is set, retaining a signaling connection to the user equipment, and triggering the server that buffers the downlink data to send the downlink data to the user equipment. The method and device for transmitting data according to the embodiments of the present invention can save power of a user equipment.