Time domain analysis on earthquake response of soil-asymmetric structure interaction system was carried out in this paper in order to study the feasibility of the forced decoupling method. Acoording to lateral-torsional coupling vibration equations of soil-asymmetric structure system, the direct integral MATLAB program in time domain were made used method. Feasibility of forced decoupling method was carried out by comparing the result in time domain with the result in frequency domain. Finally, it is derived that the results are very close to each other, which verify the feasibility of forced decoupling method. This conclusion can supply references to engineering calculation and design of structure.