Abstract: The present invention discloses an ultra-low frequency (ULF) tuned liquid mass damper, and relates to the technical field of bridge vibration control. The tuned damper includes a damping box which is provided with a spring set secured at one end to the damping box, the other end connected with a mass block. The damping box is filled with damping liquid, and the mass block is completely immersed or partially immersed in the damping liquid. The damping ratio of the ULF tuned liquid mass damper ranges from 3% to 35%, and the inherent frequency 0.05 to 0.5 Hz. The ULF tuned liquid mass damper, according to the present invention, can fully utilize the additional mass of the damping liquid, and with the buoyancy effect of the liquid, maintain the frequency of structural vibration below 0.