Here, we are going to design a stabilized controller for the Stewart platform. A new model of the Stewart platform will be presented which has many applications in the industry. The dynamics of the Stewart platform are presented in two separate systems. One system for the linear motion of the Stewart platform and another system for its angular moment. In addition, we use a quaternion-based method to analyze the dynamics of the Stewart platform. The 6-DOF Stewart-Platform dynamics is nonlinear, then at first by using the feedback linearization method we convert the nonlinear dynamics in new space as a linear state-space. Then we design an -stabilized controller for this platform in linear space. A linear controller for linear motion systems will be designed but for the second system, it must first be linearization and then design controller for it. After design of stabilized-LQR controller for linearized space system, we convert our design to original nonlinear space and exert on system for simulations. The simulations results show that we will succeed to design a controller for the Stewart platform.