The ground motion of an scalene triangular dike impacted by SH waves is discussed.The methods of complex function and moving coordinate system as well as a simple mathematic model are used here.The model is divided into two parts,a wave function which satisfies the condition of stress free at the triangular wedges is constructed in one part,and a scattered wave function which satisfies the condition of stress free at the horizontal surface is constructed in the other part.Then the moving coordinate system is used to transform the solution of this problem into a"conjunction"problem.Finally,the solution of the problem is reduced to a series of algebraic equations and can be solved numerically.Numerical examples show that the influence of incident SH wave characters on the ground motion is great,and the influence of structure on incident SH wave is significant.Compared with stiff structures,the values of ground motion and the points where they happen for soft structures are different greatly because of their good capability of energy absorption.