A method for feeding back channel state information, applicable to a coordinated multi-point, COMP, transmission system, the method comprising: feeding back channel state information to a base station by way of concatenating more than one piece of channel state information in a bit domain; wherein in feeding back channel state information on more than one carriers, the method comprises: concatenating for each cell, respectively, more than one piece of channel state information needed to be fed back; concatenating channel state information of all cells needing to feed back channel state information; and mapping the concatenated channel state information of all the cells to corresponding resources and feeding back to the base station; wherein more than one piece of rank indication information included in the more than one piece of channel state information are concatenated in the bit domain, and more than one piece of precoding matrix indication information and/or channel quality indication information included in the more than one piece of channel state information are concatenated in the bit domain, wherein, if aperiodic feedback is triggered according to a transmission point or a channel state indication reference signal, CSI-RS, resource of non-zero power, in feeding back channel state information in a channel state information set corresponding to multiple interference assumptions, the concatenating for each cell, respectively, of more than one piece of channel state information is performed in a fixed order. feeding back channel state information to a base station by way of concatenating more than one piece of channel state information in a bit domain; wherein in feeding back channel state information on more than one carriers, the method comprises: concatenating for each cell, respectively, more than one piece of channel state information needed to be fed back; concatenating channel state information of all cells needing to feed back channel state information; and mapping the concatenated channel state information of all the cells to corresponding resources and feeding back to the base station; wherein more than one piece of rank indication information included in the more than one piece of channel state information are concatenated in the bit domain, and more than one piece of precoding matrix indication information and/or channel quality indication information included in the more than one piece of channel state information are concatenated in the bit domain, wherein, if aperiodic feedback is triggered according to a transmission point or a channel state indication reference signal, CSI-RS, resource of non-zero power, in feeding back channel state information in a channel state information set corresponding to multiple interference assumptions, the concatenating for each cell, respectively, of more than one piece of channel state information is performed in a fixed order. concatenating for each cell, respectively, more than one piece of channel state information needed to be fed back; concatenating channel state information of all cells needing to feed back channel state information; and mapping the concatenated channel state information of all the cells to corresponding resources and feeding back to the base station; wherein more than one piece of rank indication information included in the more than one piece of channel state information are concatenated in the bit domain, and more than one piece of precoding matrix indication information and/or channel quality indication information included in the more than one piece of channel state information are concatenated in the bit domain, wherein, if aperiodic feedback is triggered according to a transmission point or a channel state indication reference signal, CSI-RS, resource of non-zero power, in feeding back channel state information in a channel state information set corresponding to multiple interference assumptions, the concatenating for each cell, respectively, of more than one piece of channel state information is performed in a fixed order.