The invention discloses an audio frequency acquisition method and device based on a microphone array. The method comprises the steps of: searching audio frequencies in all directions through a first microphone array; the second microphone array collecting a first target audio frequency in a first beam pointing direction; judging whether a trigger audio frequency searched by the first microphone array satisfies a predetermined switchover triggering condition; regarding the trigger radio frequency as a second target frequency if the trigger audio frequency searched by the first microphone array satisfies the predetermined switchover triggering condition, and transmitting sound source locating information of the trigger audio frequency to the second microphone array; judging whether or not a second position where the second sound source emitting the second target audio frequency is is the same with a first position where a first sound source emitting the first target audio frequency is; and if the second position is different from the first position, controlling the second microphone array to perform a beam pointing direction switch to acquire the second target audio frequency in a second beam pointing direction. The invention solves the technical problem that the audio frequencies in other directions can not be acquired due to a fixed audio acquisition direction of a single microphone array in the related technology.