Abstract: This paper discusses the difficulties met by the engineers while developing some single board/chip microcomputer based small industrial control systems, and the shortcomings existing in many current development systems. The system design criteria, system structure as well as main characters of a new single board/chip microcomputer develooment system-DESCO, are briefly introduced here. BESCO has a newly designed, linestructured, high-level programming language-LANDES, which is development system oriented, fit to the process of developing small industrial control systems. With LANDES and DESCO, users will be able to develop their objective systems effectively.