Abstract: In the analysis of high-rise building structures, the second order effect is not negligible when the structural axial force is excessive and the lateral rigidity is weak. In this paper, a very brief basic differential equation is derived for second order analysis of frame-shear wall structures. In form, it is merely a simple extension of the basic differential equation of frame-shear wall structure in first order theory. This equation is very convenient in practical use. Inaddition, "second order effect coefficient" correctly reflectS affection of various factors producing second order effect. An example is provided at the end of the paper.