The present invention discloses a four-mode defected ground structure resonator, comprising a metal dielectric substrate and a defected ground unit which is etched in one surface of the metal dielectric substrate; the shape of the defected ground unit is axially symmetric about a first central axis of the defected ground unit, and also the shape of the defected ground unit is axially symmetric about a second central axis of the defected ground unit; the first defected ground unit is provided with H-shape or quasi H-shape, the second defected ground unit is provided with L-shape, quasi L-shape, U-shape or quasi U-shape. The four-mode defected ground structure resonator of the present invention is provided with four types of resonant modes, and the four types of resonant modes are provided with good tunability.