A method for generating a codebook and a method and an apparatus for data transmission are provided. The method includes: receiving a label of a codeword sent by a User Equipment (UE); selecting the codeword identified by the label from the codebook for eight-antenna; and coding data to be sent by using the codeword. The codebook for eight-antenna includes at least one rank-8 codeword for eight-antenna. The rank-8 codeword for eight-antenna is generated by multiplying an inverse matrix of a rotation matrix for eight-antenna with an eight-dimensional matrix formed by rank-4 codewords for four-antenna; or generated by extending rank-4 codewords for eight-antenna, where the rank-4 codeword for eight-antenna is generated according to codewords for four-antenna. Therefore, the codeword in the codebook for eight-antenna is applicable to scenarios including dual-polarization strong correlation, dual-polarization weak correlation, single-polarization strong correlation, and single-polarization weak correlation, etc.