Abstract: Theoretical analysis and experimental research for modal properties of multistory buildings with damper control systems are thoroughly performed in this paper. The Veselic's global Jacobi method is employed and advanced for the modal analysis of the systems of building structures with nonclassical damping distributions, which is shown to have significant advantages. The research shows that when damper control is introduced to the multistory buildings,the modal properties will be strikingly changed along with the variations of damping factors of the damper control systems and their positions on the buildings. Finally, a 3-story frame building model is tested to verify the research results.