The motion relationship model of all axes involved in CNC hobbing machines is established. A single pitch adjustment method based on motion coupling relationship in gear hobbing is proposed. With position adjustment of only 0 to 1 pitch, the same motion coupling relationship during the whole machining process can be guaranteed. Though automatic programming system based on SINUMERIK 840D, the coupled motion control and adjustment in CNC hobbing process is realized. And practical application in CNC hobbing machines shows that this method can reduced adjustment time effectively during process, improving processing efficiency.