Some embodiments of the present disclosure provide a method and an apparatus for forming a differential beam, a method and an apparatus for processing a signal, and a chip. The method for forming a differential beam includes: obtaining a differential beam forming signal according to an input signal acquired by two microphones in a microphone array (101); and performing a nonlinear adjustment on at least an amplitude of the differential beam forming signal based on a distance between the two microphones and a signal frequency of the input signal to obtain the adjusted differential beam forming signal (102). With the above solution, a constant beam characteristic of the differential beam forming signal can be ensured as much as possible for microphone arrays of different specifications.