A permanent magnet low-frequency multidegree of freedom vibration isolation mechanism based on the negative stiffness principle comprises a lower permanent magnet, an upper permanent magnet, a rubber sheet, a lower permanent magnet fixing plate, a rubber fixing seat, an upper permanent magnet fixing plate, a rubber pressure block and a rubber sheet edge fixing pressure ring, wherein the permanent magnets are magnetized in the vertical direction and opposite for same poles. A positive stiffness system is formed by the permanent magnets under the action of repulsive force, the rubber sheet is stretched to a negative stiffness system under the action of repulsive force of the permanent magnets, two systems are combined to form a low-frequency vibration isolation mechanism, the single vibration isolation mechanism can realize three degrees of freedom low-frequency vibration isolation, and three or four systems are combined in parallel to realize the six degrees of freedom low-frequency vibration isolation. The vibration isolation mechanism can be used in vacuum without the input of external energy. The vibration isolation mechanism has the characteristics of simple structure, low cost and easy processing, and can be used in the fields like optics, acoustics, biology, advanced manufacturing equipment, semiconductor manufacturing and precision measurement, etc.