This paper describes a control system of Free Electron Laser(FEL)-THz，which is a distributed control system based on Experiment Physics and Industrial Control System(EPICS). It gives detailed description of the injector control system，magnetic bunch compressor system and transport control system，including the hardware structure and software design. It also describes the process of creating device support module for the GPIB device and RS232 serial device. The implementation provides preparations for the upgrade of the FEL-THz control system.