The present disclosure provides a method and apparatus for transmitting and receiving Channel State Information. The said transmitting method includes calculating the maximum value mH(k) of real part and imaginary part of each element in CSI matrix Heff(k) of the sub-carrier; carrying out M bit quantization to mH(k) to obtain the quantization amplitude MH(k); calculating the linear portion MHlin(k) of MH(k); using MHlin(k) for carrying out Nb bit quantization to real part and imaginary part of each element in Heff(k) respectively to obtain the quantized CSI matrix Heff(k); Nb being a positive integer; and transmitting said quantization amplitude MH(k) and said quantized CSI matrix Heffq(k).