Abstract: The control performance of Circular Tuned Liquid Column Dampers (CTLCD) to torsional response of structure excited by ground motions is investigated. Based on the motion equation of the CTLCD-structure system, the optimal control parameters of CTLCD are given through some derivations supposing that the ground motion is a stochastic process. The influence of systematic parameters on the structural equivalent damping ratio is analyzed for purely torsional vibration. The effect of systematic parameters on the structural equivalent damping ratio in translational and torsional direction is studied for torsionally coupled vibration. The results show that the Circular Tuned Liquid Column Damper (CTLCD) is an effective torsional response control device.