Machine tool vibrations have great impact on machining process. In this paper the dynamic behavior and modal parameters of surface grinding machine is presented. For this purpose, the CAD (computer aided design) model of the surface grinding machine structure is provided in catia and then Natural frequencies and mode shapes of the machine tool structure are carried out through FEM (finite element method) modal analysis under ansys. The model is evaluated and corrected with experimental results by modal testing on surface grinding machine. Finally, the natural frequencies and mode shapes obtained by both experimental and FEM modal analysis are compared. The results of two methods are in widely agreement.