The present invention provides a method for determining a precoding matrix indicator, user equipment, and a base station. The method includes: receiving a first reference signal set sent by a base station; determining, based on the first reference signal set, one or more intermediate matrices, and reporting, to the base station, a first index used to indicate the intermediate matrix; receiving a second reference signal set sent by the base station; and determining, based on the second reference signal set, a precoding matrix, and reporting, to the base station, a precoding matrix indicator used to indicate the precoding matrix, where the precoding matrix is a product W of two matrices W1 and W2, and W=W1W2, where W1 is a block diagonal matrix, W1=diag{X1,X2}. In this way, transmission performance of an active antenna system can be improved.