Disclosed is a multi-mode beam former, comprising a device for receiving a multi-mode input signal, and a device for constructing an optimization model and solving the optimization model to obtain a beam-forming weight coefficient for performing linear or non-linear combination on the multi-mode input signal. The optimization model comprises an optimization formula for obtaining the beam-forming weight coefficient. The optimization formula comprises: establishing an association between at least one electroencephalogram signal and a beam forming output, and optimizing the association to construct the beam-forming weight coefficient associated with the at least one electroencephalogram signal.