Rotating machines are basic components in various industrial applications, which are considerably vulnerable to undesired vibration. Therefore vibration of rotating systems has been studied by many researchers. In particular, rotating disks are one of the most common components in many machines and engineering devices, such as saws, and disk drives. In this research, a dynamic model is proposed, as a PDE equation, for a rotating disk. For verification of the dynamic model, natural frequencies and mode shapes are extracted by modal testing. After that, the dynamic equation is solved with using finite element method for free vibration analysis and the results are compared with the modal test results. The results represent good accuracy of the dynamic model. Next, forced vibration of the rotating disk is solved and the results are compared with different number of modes in answer with the aim to determine the effective modes. As the source of excitation on a circular saw, the cutting forces are calculated and their induced forced vibration is investigated. Then space state equation of rotating disk is extracted and active LQR controller is designed for various angular velocities. The controller is simulated in MATLAB with consideration of cutting forces and transvers forces. The results shows that in various speeds the controller has good performance, even in presence of cutting forces and chatter possibility of vibrations. Keywords: Vibration of rotating disk, Modal test, Finite element method, Active control, LQR controller