Method and device for transmitting downlink control information and determining search space

A method and device for transmitting downlink control information and determining search space, the method for determining the search space comprising: determining, according to a first offset, a second offset and other related parameters, an enhanced control channel element (eCCE) occupied by an enhanced physical downlink control channel (ePDCCH) candidate on each carrier wave. The first offset represents the adjusted offset of the eCCE in different eREG groups, the eCCE being occupied by the ePDCCH candidate in the same carrier wave; and the second offset represents the offset coordinating the collision of the eCCEs occupied by the ePDCCH candidates between different carrier waves. Under the inter-carrier condition, a first offset and a second offset are introduced during space search to prevent, as much as possible, ePDCCH candidates between CCs from colliding, and prevent, as much as possible, the ePDCCH candidate of each CC from being distributed into the same eREG group, thus solving the problem in the prior art.