Parallel robots have obtained a big attention because of their great advantages more than serial mechanism, like high stiffness, high speed and high accuracy. Parallel robots have also some drawbacks, the major of them are a limited workspace that can be seen as the intersection of the individual workspace of each serial arm and also the complicated singularities. Different methods were used to describe the problem and achieve the dynamics modeling of the robot Thus, there is still no consensus on which formulation is the best to describe the dynamics of the robot. Lagrange formulation was used in this work because it offers a well analytical and orderly structure. In order to verify the validity of the dynamic model proposed in this study, simulations of the obtained model are carried out using Matlab software.The study of the dynamics of the 3 dof parallel robot is made mostly to solve successfully the control of the motion of this robotic system.