Hysteresis hydraulic damper is based on the principle of fluid movement, when the fluid passes through the throttle hole will produce viscous resistance and is a kind of stiffness, speed related to the damper. Generally composed of cylinder, piston, piston rod, bushing, medium, pin head and other parts, the piston can be reciprocating in the cylinder, the piston is equipped with a damping structure, and the cylinder is filled with fluid damping medium. Viscous damper adopts low viscosity silicone oil as the medium, and the damping characteristics are realized by the principle of small hole excitation. From the working principle, the design of the damping structure, the life and reliability of the product, compared with the previous types of dampers have undergone revolutionary changes, representing the highest level of development of the current viscous damper technology.