A method for applying accuracy compensation to a computer numerically controlled (CNC) machine can compensate control program that controls the CNC machine. The method recognizes an actual outline of the product using an image of product produced by the CNC machine controlled by the control program, and further obtains an ideal outline of the product. The method obtains compensation values by computing coordinate differences between points of the actual outline and points on the ideal outline, and compensates the control program using the compensation values.