The paper introduces a river model cross-section board auto-processing system based on a CNC engraving machine, in which an optimum sorting algorithm is used for making model cross-section boards as much as possible on a wood-board. The system can improve the utilization of the material, reduce production cost and guarantee processing quality. Meanwhile,owing to considering the cutter compensation in numerical control processing, the accuracy of model board is enhanced, and because of the system adopts a network construction to realize the remote control, it is very easy to be used.