This paper present a control system with ADRC for a linear direct-direct AC servo system. In this control system, the ADRC is used for the speed regulation, and the current loop is designed independently to a better performance servo amplifier. Where, the ADRC design is the key process. Through using the ADRC, the speed regulation system is simplified. The simulation results prove the system has good control performance. Through choosing and changing the parameters, the feasibility, adaptability and robust of the controller are testified by the results.