The goal of this research is to improve the dynamic behavior of the aluminum CNC machining center. In order to accomplish this aim, first, the machine is digitally modeled to make the geometry suitable and simpler for the analysis software. Secondly, the digital model is analyzed by the ANSYS modal analysis tool with the gravity effect, and the mode shapes are gathered. Due to the very low stiffness of the M/T cabin, the cabin is excluded from the analysis after it is proved that the cabin has almost no effect on machining dynamics. Then, modal parameters gathered by ANSYS are compared with the impact hammer test to verify the digital modeling process. According to this comparison, the difference between the impact hammer test and modal analysis is acceptable, indicating that modeling was successful. After verification of modeling, topology optimization, which aims to increase the stiffness of the machine structure, has been carried out. Further improvements obtained be based on mode shapes, natural frequencies, and stability lobes.