Embodiments of the present invention disclose a pre-coding method and a transmitter used in a distributed multiple input multiple output (MIMO) system. The method comprises that a dual interference channel is constructed, an interference alignment iterative calculation is performed on a pre-coding matrix in an original channel by utilizing the transformation relationship between the dual interference channel and an original interference channel; on the one hand, as the times of iterative calculation increases, the calculated pre-coding matrix in the original channel can gradually converge, and on the other hand, the total mean square error (MSE) of the interference channel system calculated from the pre-coding matrix of the original channel obtained according to the final calculation also tends to the minimum, so that the minimum of the MSE is achieved, and the mutual interference of the signals between different users is reduced.