A precoding method and apparatus are disclosed. The corresponding method includes: constructing a Lagrange function according to a precoding matrix, transmit power, a receive filter matrix and a weighting matrix, and obtaining a Lagrange multiplier by using the Lagrange function; updating the precoding matrix according to the Lagrange multiplier to obtain an iterative precoding matrix and an iterative receive filter matrix; obtaining an iterative Lagrange multiplier according to the iterative precoding matrix, the transmit power, the iterative receive filter matrix and the weighting matrix, and repeating the above steps in an iterative manner of updating the iterative precoding matrix according to the iterative Lagrange multiplier till the iterative precoding matrix converges to a threshold; and precoding information to be transmitted according to the iterative precoding matrix converging to the threshold.