There is disclosed method for reporting channel state so as to report channel state based upon CSI-RS. The method includes: a UE detecting configuration information of Channel State Information-Reference Signal (CSI-RS), determining according to detection result the number of ports required to report channel state based upon CSI-RS, the UE determining CSI-RS based PMI feedback scheme to be adopted in preset corresponding relationship between the number of ports and feedback scheme upon determining that the eNB is to map data of Physical Downlink Shared Channel (PDSCH) onto P (number) CSI-RS ports for transmission in a codebook-based precoding scheme, wherein the codebook-based precoding scheme is a scheme as represented in the formula of [ y ( 0 ) ⋮ y ( P - 1 ) ] = W · s , wherein W represents a codebook consisted of a precoding matrix, S is PDSCH data consisted of data layers whose quantity is equal to value of Rank Indication (RI) and   [ y ( 0 ) ⋮ y ( P - 1 ) ] represents a vector consisted of data on P (number) CSI-RS ports; and the UE calculating and reporting channel state information according to the determination result. The invention further discloses apparatus for performing the method.