Abstract: The software and hardware system was developed for use with the German BRUKER ANALYTISCHE MESSTECHNIK COMPANY'S EPR Spectrometer model ER-200D-SRC. The system was used to control spectrometer during magnetic sweeping,collect data from spectral scans in single-scan and multiscan modes, data analysis and manipulation, output data to the spectrometer x-y recorder and print data to printer,The hardware is based on IBM PC/386 computer and two interface modules, one of which is commercialized 12-bit A/D and D/A interfaced, and the other a designed digital I/O control card with a general programable interface IC INTEL 8255 being it's main body.The two cards can be inserted into PC's extension socket respectively. The software,written in C language, is characterized by chinese character menu display,structured and modularized program and real-time working.It has good user's interface and easy operation, The system has recovered and im-proved the whole funtion of the original spectrometer and has certain value for development.

Key words: Microcomputer, EPR spectrometer