In this paper,a control system based on double neural networks-PI for 3-RPS parallel mechanism is presented to aim for the nonlinear modeling and controlling.The control system is composed of three linear controllers,one neural network controller (NNC) for compensating the nonlinear modeling and one neural network identification (NNI) for the controlling model.Simulation results have shown that the response time,movement accuracy and resistance to load disturbance of the 3-RPS parallel mechanism sYstem canbe improved using the double neural networks-PI.