The invention provides a self-learning error correction system and method for a numerically-controlled machine tool, which belongs to the field of servo system control. The system provided by the invention comprises a trajectory generation module, a position loop iterative learning controller, a second controller, a motor and a transmission module. The output end of the trajectory generation module is connected with the input end of the position loop iterative learning controller. The input end of the second controller is connected with the output end of the position loop iterative learning controller. The output end of the second controller is connected with the input end of the motor and the transmission module. The system further comprises an outer layer self-learning speed planner. The input end of the outer layer self-learning speed planner is connected with the output end of the motor and the transmission module. The outer layer self-learning speed planner is connected with the trajectory generation module. The system and the method have the advantages that a numerically-controlled system has the self-learning function of error experience accumulation and autonomous error correction in repeated processing; the processing process of the numerically-controlled machine tool becomes the process of automatic learning; and the processing yield is greatly improved.