In this paper, a design method of frequency-domain damping(FDD) to improve stability is proposed. In recent days, haptics is one of major topics in robotics field. Especially tele-operation with haptic feedback has been studied for long years, but problem of time delay still exists. Time delay causes three problems : operational force, oscillating motion, and degrading of contact stability. To solve both problem of operational force and contact stability, FDD is proposed. Though FDD is designed to improve stability, conventional design has a possibility of destabilization. Furthermore, delay time model is needed to design filter and frequency of human motion should be known but these elements are nonlinear. This paper considers these problems and propose a design method of FDD. By using this design, problem of operational force, oscillating motion caused by time delay, and degrading of contact stability are improved. Validity of proposed method is confirmed by simulation study and experiment.