A method for transmitting channel status information, CSI, of downlink, DL, multi-carrier transmission, the method comprising: generating two CSIs for two downlink component carriers, CCs, wherein each of the two CSIs includes at least one of a rank indicator, RI, a wideband first precoding matrix index, WB first PMI, a wideband second PMI, WB second PMI, a subband second PMI, SB second PMI, a wideband channel quality indicator, WB CQI, a subband CQI, SB CQI, or a precoding type indicator, PTI; determining (S3520, S3530), when the two CSIs collide with one another in one uplink, UL, subframe of one UL carrier, a CSI of the two CSIs to be transmitted on the basis of priority; and transmitting the determined CSI over a UL channel, characterized in that each of the two CSIs is classified into a first report type group including a plurality of report types which indicate at least the RI, a second report type group only including a report type which indicates the WB first PMI, a third report type group including a plurality of report types which indicate at least the WB CQI, or a fourth report type group including a plurality of report types which indicate at least the SB CQI, wherein the priority is defined that, if a CSI of the first report type group or a CSI of the second report type group collides with a CSI of the third report type group or a CSI of the fourth report type group, the CSI of the third or fourth report type group has lower priority than the CSI of the first or the second report type group and is dropped, wherein the CSI of the first report type group and the CSI of the second report type group have the same priority, and wherein the WB CQI is calculated based on precoding information determined by using the WB first PMI. generating two CSIs for two downlink component carriers, CCs, wherein each of the two CSIs includes at least one of a rank indicator, RI, a wideband first precoding matrix index, WB first PMI, a wideband second PMI, WB second PMI, a subband second PMI, SB second PMI, a wideband channel quality indicator, WB CQI, a subband CQI, SB CQI, or a precoding type indicator, PTI; determining (S3520, S3530), when the two CSIs collide with one another in one uplink, UL, subframe of one UL carrier, a CSI of the two CSIs to be transmitted on the basis of priority; and transmitting the determined CSI over a UL channel, characterized in that each of the two CSIs is classified into a first report type group including a plurality of report types which indicate at least the RI, a second report type group only including a report type which indicates the WB first PMI, a third report type group including a plurality of report types which indicate at least the WB CQI, or a fourth report type group including a plurality of report types which indicate at least the SB CQI, wherein the priority is defined that, if a CSI of the first report type group or a CSI of the second report type group collides with a CSI of the third report type group or a CSI of the fourth report type group, the CSI of the third or fourth report type group has lower priority than the CSI of the first or the second report type group and is dropped, wherein the CSI of the first report type group and the CSI of the second report type group have the same priority, and wherein the WB CQI is calculated based on precoding information determined by using the WB first PMI.