For an astronomical telescope mount, having a high stiffness to support the mirror cell and instruments is its basic function. Traditionally, the mount is composed of azimuth base, azimuth axis, fork, altitude axis, tube, top-ring, etc. On the other hand, telescope will be driven to track the observing objects during operation. So, for the mechanical structure

design engineer, finding a high stiffness-to-weight ratio mount is the main task. Finite element method (FEM) is a powerful tool to help structure design engineer to achieve this goal. ANSYS is one of these kinds of finite element method software. In this paper, with the help of ANSYS, the static and dynamic analysis, calculation and optimization of  a 2.5m telescope mount will be given. The FEM results show that the structure, designed for 2.5m telescope, is feasible and reliable and have a high stiffness-to-weight ratio to meet the optical demands.