Abstract: Using the continuum model, this paper made a study on buckling of coupled shear walls. A closed form solution and an explicit formula for the buckling load were obtained. The form of the formula implies that the coupled shear wall is a kind of dual structural system, and the interaction between two structural components may be elucidated by a series-parallel circuit. Based on this circuit, an explicit expression for the lateral stiffness of coupled shear wall was found and compared with the exact solution. Amplification factors of drift, bending moments and axial forces in walls and bending moments in the link beams due to the second order effect were studied and a simple formula for the amplification factor was also provided.