A new method of semi-active control on cable-MR system based on fuzzy logical theory in this article is presented. In the method, the voltage to drive MR damper is determined by fuzzy controller, which avoids the difficulty of calculating the voltage from the strong nonlinear MR model. In order to testify the effectiveness of the proposed method, the simulation analysis to a typical cable is made and its results are compared to the passive control (passive-on, passive-off) of MR and active control (LQR). The conclusion is that the operation of fuzzy control method is simple and practical. Its effect is better than the passive methods, but is a little worse than LQR.