A data transmission terminal, characterized by comprising: an establishing unit, configured to establish an interference mapping table according to interference between the data transmission terminal and second user terminals beyond a cell of the data transmission terminal; a finding-out unit, configured to find out multiple second user terminals having small interference on the data transmission terminal according to the interference mapping table; a selecting unit, configured to select an available second user terminal having a minimum interference from the multiple second user terminals having small interference on the data transmission terminal; wherein the degree of small interference is selected differently according to different conditions; and a transmitting unit, configured to multiplex an uplink time-frequency resource of the available second user terminal having the minimum interference to perform device to device, D2D, data transmission; wherein the establishing unit is specifically configured to: detect physical downlink control channel, PDCCH, of the second user terminals beyond the cell of the data transmission terminal; perform PDSCH signal energy detection on a sub-frame corresponding to time-frequency resource information indicated by the PDCCH of the second user terminals when transmitting data; the smaller the PDSCH signal energy is, the smaller the interference between the data transmission terminal and the second user terminals is; and establish the interference mapping table according to a detection result; wherein the detecting PDCCH of the second user terminals beyond the cell of the data transmission terminal, comprises: detecting the PDCCH of the second user terminals through ID of the second user terminals. an establishing unit, configured to establish an interference mapping table according to interference between the data transmission terminal and second user terminals beyond a cell of the data transmission terminal; a finding-out unit, configured to find out multiple second user terminals having small interference on the data transmission terminal according to the interference mapping table; a selecting unit, configured to select an available second user terminal having a minimum interference from the multiple second user terminals having small interference on the data transmission terminal; wherein the degree of small interference is selected differently according to different conditions; and a transmitting unit, configured to multiplex an uplink time-frequency resource of the available second user terminal having the minimum interference to perform device to device, D2D, data transmission; wherein the establishing unit is specifically configured to: detect physical downlink control channel, PDCCH, of the second user terminals beyond the cell of the data transmission terminal; perform PDSCH signal energy detection on a sub-frame corresponding to time-frequency resource information indicated by the PDCCH of the second user terminals when transmitting data; the smaller the PDSCH signal energy is, the smaller the interference between the data transmission terminal and the second user terminals is; and establish the interference mapping table according to a detection result; wherein the detecting PDCCH of the second user terminals beyond the cell of the data transmission terminal, comprises: detecting the PDCCH of the second user terminals through ID of the second user terminals. detect physical downlink control channel, PDCCH, of the second user terminals beyond the cell of the data transmission terminal; perform PDSCH signal energy detection on a sub-frame corresponding to time-frequency resource information indicated by the PDCCH of the second user terminals when transmitting data; the smaller the PDSCH signal energy is, the smaller the interference between the data transmission terminal and the second user terminals is; and establish the interference mapping table according to a detection result; wherein the detecting PDCCH of the second user terminals beyond the cell of the data transmission terminal, comprises: detecting the PDCCH of the second user terminals through ID of the second user terminals.