Embodiments of the present invention provide a method, an apparatus and a system for multi-antenna transmission, wherein a third precoding matrix determined by a sending end device is a function of a first precoding matrix and a second precoding matrix. That the first precoding matrix has a block diagonal structure and that sub-matrices corresponding to two blocks are Hermitian matrices enable the above-mentioned third precoding matrix to match with a transmit spatial autocorrelation matrix of a cross-polarized antenna or a distributed antenna, thereby enhancing precoding performance and improving system throughput effectively.