An interference alignment method, an interference alignment device, and a multi-channel communication system are provided. The method includes: obtaining channel matrix in a multi-channel communication system; determining a first desired signal and a second desired signal of the multi-channel communication system according to the channel matrix; obtaining precoding vectors and receive vectors, after a first receive signal is filtered by a receive vector corresponding to the first desired signal, a signal formed by superposing interference signals included therein has a feature of a lattice constellation pattern, and that at a receiver corresponding to the second desired signal, after a second receive signal is filtered by a receive vector corresponding to the second desired signal, interference signals included therein are canceled, where the first receive signal and the second receive signal are transmit signals sent to the corresponding receivers after precoding processing is performed at transmitters by using corresponding precoding vectors.