The present invention relates to the acoustic metamaterial structural unit with the function of soundproof, flow-passing and heat-transferring enhancement, which comprises a frame, a constraint placed in the frame and a piece of membrane covering at least one surface of the frame; both the frame and the membrane are respectively placed at least one hole. Besides, the present invention also provides the acoustic metamaterial composite plate and the composite structure constructed with the acoustic metamaterial structural unit; the method for adjusting the frequency and the assemble method. The present structural unit possesses better soundproof property than the routine perforated plated or micro-perforated plate in broad operating frequency. And also the enough heat flow, gas flow or fluid flow can pass through smoothly. The diffuse efficiency of the heat energy of the mediums on both sides of the hole is increased by the vibration of the self-structure under the excitation of the soundwave and further the efficiency of heat exchange is accelerated. The method for assembling the acoustic metamaterial composite structure with the acoustic metamaterial structural units is simple. The operation performance is steady.