The invention discloses a 3D (three-dimensional) MU-MIMO (multiple user-multiple input multiple output) precoding method based on an orthogonal joint codebook set, and relates to the technical field of mobile communication. The method comprises the following steps of enabling a base station terminal to adopt a uniform surface antenna matrix, and simultaneously store the orthogonal joint codebook set together with a user terminal; according to a 3D MIMO channel matrix, enabling the user terminal to select the optimum precoding vector in the horizontal dimension and the vertical dimension; feeding the corresponding number of the precoding vector back to the base station terminal, enabling the base station terminal to form a 3D precoding matrix, and sending signals to a plurality of users to carry out the 3D precoding processing. The method has the advantages that the orthogonal joint codebook set covers larger space, and the orthogonality is formed between the codebooks, so the matching of the 3D MIMO channel is more accurate and comprehensive, and the interference of MU channel sharing is effectively inhibited; meanwhile, by selecting the optimum precoding matrix, under the condition of not increasing the feedback amount, the channel information in the horizontal dimension and the vertical dimension are comprehensively utilized, and the integral property of the system is improved.