In the noncircular gear grinding methods using gear generator with form-grinding process, grinding headstock and workpiece may appear interference collision. The form-grinding radius selection problem based on the shaper has been discussed. Based on the designed grinding head, an effective form-grinding radius choose method and the head stock interference detection system has been established. This detection system is directly used in the grinder machining process; the solutions to the problems of both grinding head interference inspection and form-grinding radius selection in the grinding machine design process are introduced. In this paper, we briefly introduced the process for the design of inspection system and the relative algorithm of the method. Finally, The Program flow chart of the program design and implementation process was given and actual example of an outside triangle gear machining results is given, which validates the reliability of the system.