To assist NC part programming, a compiler system for a part programming language is designed. Using the part programming language, the workpiece configuration in 2-half dimension can be conveniently defined and NC machine instruction codes for the workpiece are automatically generated by compiler system. The NC machine FANUC 3000C is used as target machine, and an amount of fundamental function and code is treated and reflected on. The part programming language covers geometric property and machine related information. The compiler is written in C language utilizing software tools (LEX, YACC) and, implemented on VAX 11-780 in the Dep. of computer science. For the verification of the part programming, a graphic interface is developed in order to display the contour of the workpiece on a TEXTRONIX 4010 terminal. To be used in industrial fields, the system should be improved and tested, especially in the code generation module. For this, knowledge about NC machine system and technical experience in tooling(cutting) are required. If the proper functions to satisfy above technical problems are added to this system, it is expected that this is used as a convenient software tool in NC programming.