The present invention discloses a metamaterial, and a method and an apparatus for adjusting a frequency of the metamaterial. The metamaterial includes a substrate material, and an electrically controllable microstructure unit array disposed on the substrate material and including a plurality of electrically controllable microstructure units. Each electrically controllable microstructure unit includes an external metal structure, an internal metal structure, and a varactor diode. The internal metal structure and the external metal structure define a ring-shaped channel. The varactor diode is disposed in the ring-shaped channel of each electrically controllable microstructure unit, and is configured for adjusting an operating frequency of each electrically controllable microstructure unit according to a voltage applied across the varactor diode. According to the present invention, a technical problem of failing to quickly and accurately adjust an operating frequency of the metamaterial in the prior art is solved.