Abstract: The boundary integral equations of inhomogeneous elastic and viscoelastic soil mass were derived through the use of fictitious forces and integral transformation technique. The numerical method for solving these equations was described. This method is analogical to the boundary element method for homogeneous elastic solids. It does not require to solve the problems by zoning technique and time steps so that the solution scheme is simplified and calculations can be largely reduced. The application of this method to geotechnique was briefly presented in this paper.