A speaker array control method includes steps of detecting a position of an audience located in front of a speaker array, wherein the speaker array includes N speakers and N is a positive integer larger than one; defining a target and a non-target with respect to an i-th speaker of the N speakers according to the position of the audience, wherein i is a positive integer smaller than or equal to N; calculating a weighting vector for the i-th speaker according to the target and the non-target; adjusting a directionality of an output signal of the i-th speaker by the weighting vector and reducing energy of a plurality of side lobes of the output signal of the i-th speaker; and controlling the i-th speaker to output the adjusted output signal when the energy of each of the side lobes is smaller than a threshold.