The main purpose of this thesis is to design a positioning system that matches the demand of the high-accuracy and the high-speed positioning. Hereon, the linear DC motor will be chosen as the main body of the whole system. Individually, we design the controller for macro model and micro model. Among them, using the genetic algorithms¡]GA¡^to find the near-optimum controller parameters for PID controller to complete the macro target. And adopting the relay-feedback auto-tuning PID controller to carry out the micro region position control. Through the dynamic transition condition, the two-step position control system is integrated. We hope that the positioning results can achieve the position sensor resolution, , in 0.2 second¡]positioning distance <1.0cm¡^. By adopting the principle and operation procedure of the genetic algorithms to make a search for the near-optimum controller parameters, and through the process of selection, reproduction, crossover, and mutation of genes, and then the performance of the closed-loop system with PID controller is improved. According to the computer simulations and the experimental results, it is obvious that the GA-based near-optimal controller can satisfactorily control the linear DC motor system.