A method for transmitting a physical downlink channel, performed by a base station of a communications system, and comprising: transmitting, by the base station, a narrowband physical downlink control channel, NB-PDCCH, which should be transmitted in one subframe, in an n th downlink subframe to a user terminal, wherein the NB-PDCCH is mapped to an NB-PDCCH mapped basic element, the NB-PDCCH mapped basic element comprises a first frequency resource in a frequency domain and comprises at least one orthogonal frequency division multiplexing, OFDM, symbol comprised in the n th downlink subframe in a time domain, a bandwidth of the first frequency resource is less than or equal to 180 kHz, and n≥1; wherein if the base station transmits a narrowband physical broadcast channel, NB-PBCH, or a narrowband synchronization signal, NB-SS, in an (n+a) th or (n-a) th downlink subframe, transmitting, by the base station, the NB-PDCCH in blank symbols in the (n+a) th or (n-a) th downlink subframe, wherein the (n+a) th downlink subframe is a first downlink subframe after the n th downlink subframe, the (n-a) th downlink subframe is a first downlink subframe before the n th downlink subframe, the blank symbols are first b consecutive OFDM symbols after all OFDM symbols in the downlink subframe for transmitting the NB-PBCH or the NB-SS are arranged in ascending time order, a>0, b is equal to 3 or 5, based on a number of OFDM symbols not used for transmitting the NB-PBCH or the NB-SS in the downlink subframe, and the NB-SS comprises a narrowband primary synchronization signal, NB-PSS, or a narrowband secondary synchronization signal, NB-SSS wherein with respect to an i th OFDM symbol in the blank symbols, the NB-PDCCH mapped to an i th OFDM symbol after all OFDM symbols in the n th downlink subframe are arranged in ascending time order is repeatedly transmitted in the i th OFDM symbol in the blank symbols, and i≤5. transmitting, by the base station, a narrowband physical downlink control channel, NB-PDCCH, which should be transmitted in one subframe, in an n th downlink subframe to a user terminal, wherein the NB-PDCCH is mapped to an NB-PDCCH mapped basic element, the NB-PDCCH mapped basic element comprises a first frequency resource in a frequency domain and comprises at least one orthogonal frequency division multiplexing, OFDM, symbol comprised in the n th downlink subframe in a time domain, a bandwidth of the first frequency resource is less than or equal to 180 kHz, and n≥1; wherein if the base station transmits a narrowband physical broadcast channel, NB-PBCH, or a narrowband synchronization signal, NB-SS, in an (n+a) th or (n-a) th downlink subframe, transmitting, by the base station, the NB-PDCCH in blank symbols in the (n+a) th or (n-a) th downlink subframe, wherein the (n+a) th downlink subframe is a first downlink subframe after the n th downlink subframe, the (n-a) th downlink subframe is a first downlink subframe before the n th downlink subframe, the blank symbols are first b consecutive OFDM symbols after all OFDM symbols in the downlink subframe for transmitting the NB-PBCH or the NB-SS are arranged in ascending time order, a>0, b is equal to 3 or 5, based on a number of OFDM symbols not used for transmitting the NB-PBCH or the NB-SS in the downlink subframe, and the NB-SS comprises a narrowband primary synchronization signal, NB-PSS, or a narrowband secondary synchronization signal, NB-SSS wherein with respect to an i th OFDM symbol in the blank symbols, the NB-PDCCH mapped to an i th OFDM symbol after all OFDM symbols in the n th downlink subframe are arranged in ascending time order is repeatedly transmitted in the i th OFDM symbol in the blank symbols, and i≤5.