A method for transmitting an Enhanced Physical Downlink Control Channel, E-PDCCH, said method comprising: when downlink control information needs to be transmitted to a User Equipment, UE, in a current sub-frame in a localized transmission mode, selecting, by a base station, at least one available localized Enhanced Control Channel Element, E-CCE, in a localized E-PDCCH time-frequency resource region of the current sub-frame at a current aggregation level; and transmitting, by the base station, the downlink control information to the UE in the selected localized E-CCE; wherein the localized E-PDCCH time-frequency resource region comprises at least one E-PDCCH resource cluster, each of which consists of at least one Physical Resource Block, PRB, pair consecutive in frequency domain in the current sub-frame; and each E-PDCCH resource cluster comprises at least one localized E-CCE, and each localized E-CCE is a set of a part of Resource Elements, REs, in a PRB pair; wherein transmitting, by the base station, the downlink control information to the UE in the selected localized E-CCE comprises: determining, by the base station, a DMRS port corresponding to the selected localized E-CCE according to a correspondence relationship, between the localized E-CCE and the DMRS port, preset for the E-PDCCH resource cluster where the selected localized E-CCE is located, and transmitting a Reference Signal, RS, for demodulation to the UE via the determined DMRS port; said method being characterized in that: when there are a plurality of localized E-CCEs selected, one of DMRS ports corresponding to the selected plurality of localized E-CCEs is selected according to Equation 3 below, and the RS for demodulation is transmitted to the UE via the selected DMRS port: n port = f n eCCE lowest + RNTI mod L ′, wherein n port represents index of a DMRS port, L' represents the number of localized E-CCEs occupied by the localized E-PDCCHs in a PRB pair, n eCCE lowest represents serial number of one of the current L' localized E-CCEs with a lowest serial number, and the function f() represents index of a DMRS port corresponding to serial number of a localized E-CCE, calculated in expression bracketed in Equation 3, derived according to the correspondence relationship, and RNTI is a Radio Network Temporary Identity of said UE. when downlink control information needs to be transmitted to a User Equipment, UE, in a current sub-frame in a localized transmission mode, selecting, by a base station, at least one available localized Enhanced Control Channel Element, E-CCE, in a localized E-PDCCH time-frequency resource region of the current sub-frame at a current aggregation level; and transmitting, by the base station, the downlink control information to the UE in the selected localized E-CCE; wherein the localized E-PDCCH time-frequency resource region comprises at least one E-PDCCH resource cluster, each of which consists of at least one Physical Resource Block, PRB, pair consecutive in frequency domain in the current sub-frame; and each E-PDCCH resource cluster comprises at least one localized E-CCE, and each localized E-CCE is a set of a part of Resource Elements, REs, in a PRB pair; determining, by the base station, a DMRS port corresponding to the selected localized E-CCE according to a correspondence relationship, between the localized E-CCE and the DMRS port, preset for the E-PDCCH resource cluster where the selected localized E-CCE is located, and transmitting a Reference Signal, RS, for demodulation to the UE via the determined DMRS port; said method being characterized in that: when there are a plurality of localized E-CCEs selected, one of DMRS ports corresponding to the selected plurality of localized E-CCEs is selected according to Equation 3 below, and the RS for demodulation is transmitted to the UE via the selected DMRS port: n port = f n eCCE lowest + RNTI mod L ′, wherein n port represents index of a DMRS port, L' represents the number of localized E-CCEs occupied by the localized E-PDCCHs in a PRB pair, n eCCE lowest represents serial number of one of the current L' localized E-CCEs with a lowest serial number, and the function f() represents index of a DMRS port corresponding to serial number of a localized E-CCE, calculated in expression bracketed in Equation 3, derived according to the correspondence relationship, and RNTI is a Radio Network Temporary Identity of said UE. when there are a plurality of localized E-CCEs selected, one of DMRS ports corresponding to the selected plurality of localized E-CCEs is selected according to Equation 3 below, and the RS for demodulation is transmitted to the UE via the selected DMRS port: n port = f n eCCE lowest + RNTI mod L ′, wherein n port represents index of a DMRS port, L' represents the number of localized E-CCEs occupied by the localized E-PDCCHs in a PRB pair, n eCCE lowest represents serial number of one of the current L' localized E-CCEs with a lowest serial number, and the function f() represents index of a DMRS port corresponding to serial number of a localized E-CCE, calculated in expression bracketed in Equation 3, derived according to the correspondence relationship, and RNTI is a Radio Network Temporary Identity of said UE.