Disclosed in the invention are a method and a device for transmitting downlink control information (DCI). The method comprises: processing the downlink control information to generate downlink control information code words; scrambling and modulating the downlink control information code words in turn to generate a modulation symbol sequence; mapping the modulation symbol sequence to v data layers, wherein v is an integer which is more than or equal to 1; mapping modulation symbols on the v data layers to a demodulation reference signal (DMRS) antenna port; and mapping the modulation symbols on the DMRS antenna port to a physical antenna and sending to user equipment (UE). According to the method and the device of the invention, multi-layer data transmission can be supported, the transmission mode is more flexible, and transmission efficiency is higher.