Abstract: In order to study the influence of asymmetric foundation on soil-irregular structure system, the vibration equation considering foundation with mass eccentricity and stiffness eccentricity was established. A MATLAB program was developed based on the solution of the vibration equation decoupled by forcing decoupling method to analyze the influence of two kinds of foundation eccentricity on the structure. It concluded that mass eccentricity of foundation has slight impact on the structure, but the stiffness eccentricity has a large influence on the structure, especially on the torsional response. The conclusions derived by parametric research previously are verified by time history analysis of interaction system with foundation stiffness eccentricities of 0.6 and 0.6.