In order to improve the machining precision of gears, to embed the independent researched control algorithm, a gear machining CNC system based on embedded system was presented. The overall framework of the system was constructed, several functional modules were designed. By analyzing shaper cutter trajectory and the motion relationship between the shaper cutter and the work piece, the coordinates of key points were calculated,so the mathematical models of the shaper cutter machining automatic programming was built. On the hardware platform of the system, the shaper cutter machining automatic programming function module was successfully achieved. The research provides references for improving the gear NC control precision in the future.