A new semi-active MR-TMD control device, which is consisted of TMD which take the gasifier as the damper mass and a magneto-rheological damper, was proposed to solve the problem of factory building vibration when the gasifier is working in it. The feasibility and effectiveness of semi-active MR-TMD control system for structural vibration control under rectangular periodic excitations were simulated and analyzed by adopting one semi-active control algorithm proposed by the author. The control effect of semi-active MR-TMD, passive TMD and active AMD were compared by adopting the same model structure. Numerical simulations show that the damping performance of using semi-active MR-TMD control is better than that of using passive TMD control and active AMD control; the displacement and acceleration of the structure’s each floor have decreased significantly. It also indicates that the semi-active controlling method is available.