Abstract: The assumption of circular cross-section motion is presented for circular cylindrical shell, and the effect of rings is reduced to line forces from the acoustic viewpoint, and then the theoretical governing equation of non-uniformly ring stiffened and simple supported circular cylindrical shells is derived using Hamilton Principle. The radial modal mechanical impedance is studied by assuming a solution of standing wave form for the vibration system. The analysis shows that the radial modal mechanical impedance of ring and shell is combined in manner of series connection for the stiffened cylindrical shell, and the vibration reduction can be implemented by adjusting the geometry parameters to increase the radial modal mechanical impedance of rings. A new design method utilizing the anti-resonance of rings is also proposed for vibration reduction of ring stiffened cylindrical shell.