The control system for the JAERI-FEL consists of the hardware control process and the simulator process. The design concept is based on the hierarchical structure to separate the machine dependent parts. The system is implemented on the LAN of MS-DOS machines. The user interface employs the windows system basically; Smalltalk which has a good graphical user interface is used as a primary language at the top layer of the hierarchy. The control system includes several support tools such as a beam optics code, a data base manager, and a guidance system. Using such a control system, the development/ maintenance/ update tasks become easy and advanced control can be attainable.