The invention relates to a self-adaptive variable-damping shear thickening fluid vibration absorber. The vibration absorber comprises a piston component, a cylinder block and a sealing cover component; a closed cavity is formed by an upper inner cover, a lower inner cover, the cylinder block and a piston rod together and contains a shear thickening fluid; Y-shaped sealing rings are arranged between the piston rod and the upper inner cover and between the piston rod and the lower inner cover; and O-shaped sealing rings are arranged between the cylinder block and the upper inner cover and between the cylinder block and the lower inner cover. The piston rod is connected with a controlled structure and drives a piston to move inside the cylinder block along with vibration of the controlled structure, the shear thickening fluid outputs the variable damping force with the change of the loading frequency and amplitude, and thus the self-adaptive damping vibration attenuation effect is achieved; and meanwhile, a small overflowing hole is formed in the upper inner cover, so that the jamming phenomenon is prevented. Thus, the self-adaptive variable-damping shear thickening fluid vibration absorber has the advantages that the vibration absorber is passive, self-adaptive and simple in structure and is very applicable to the mechanical vibration control simplification requirement.