The present disclosure discloses a method, a user equipment and a base station for determining a PMI. The method includes: receiving a reference signal set sent by a base station; based on the reference signal set, selecting a precoding matrix from a codebook, the codebook at least including a non-constant modulus precoding matrix, the non-constant modulus precoding matrix at least including a non-constant modulus column vector, amplitude values of at least two elements of the non-constant modulus column vector forming a symmetrical sequence; and sending a PMI to the base station, the PMI corresponding to the selected precoding matrix. According to the method, the user equipment and the base station for determining PMI, because the non-constant modulus precoding matrix included in the adopted codebook can adjust the shape of a beam, antennas may focus power on a hotspot region, and thus a load balance may be effectively realized.