The invention relates to an intelligent knife-sharpening system of a cutting machine, and an intelligent knife-sharpening method thereof. The intelligent knife-sharpening system comprises a cutting knife, a knife-sharpening unit, an imaging unit and a cutting knife changing step execution unit, wherein the abovementioned units are connected with a main control unit through a data line respectively; the imaging unit conveys original image data of the cutting knife, and image data after the cutting knife is worn, which is obtained through regular scanning during a cutting process, to the main control unit; the main control unit compares the original image data of the cutting knife with the image data after the cutting knife is worn according to an internal judgment processing program; and the main control unit sends an instruction to drive the knife-sharpening unit to sharpen the cutting knife if a comparison result achieves a threshold value of knife-sharpening model data, and sends an instruction to drive the cutting knife changing step execution unit to change the cutting knife if the comparison result achieves the threshold value of the knife-sharpening model data. The system and the method have the characteristics of being relatively simple in structure, convenient to operate, safe and reliable in use, and the like.