By the analysis of roller gear processing technology,combining with gear meshing mechanism and motion relationship,models for rolling gear machining parameter and zero-programming are established. In this paper,the automatic generation technology of NC program for CNC gear machining process has been studied and the zero-programming system architecture of open CNC gear-hobbing machine has been presented. In the design and development of the system,human computer interaction,programming algorithm and the design of each function module have bean done. Application test shows that the expected design requirements have been achieved. By the analysis of roller gear processing technology, combining with gear meshing mechanism and motion relationship, models for rolling gear machining parameter and zero-programming are established. In this paper, the automatic generation technology of NC program for CNC gear machining process has been studied and the zero-programming system architecture of open CNC gear-hobbing machine has been presented. In the design and development of the system, human computer interaction, programming algorithm and the design of each function module have bean done. design requirements have been achieved.