The invention discloses a system parameter optimized distribution method for a numerically-controlled machine tool. The system parameter optimized distribution method comprises the following steps: (1) building a parameter model which represents the coupling relation between a servo system and a mechanical system of a numerically-controlled machine tool actuating parameter optimized distribution; (b) inputting an excitation signal into the numerically-controlled machine tool actuating parameter optimized distribution, measuring to obtain corresponding response signals, and building a transfer function between the excitation signal and the response signal; (c) converting the transfer function, identifying all modules together with the built parameter model and solving unknown parameters; (d) taking the solved parameters as performance parameters for actuating numerical control processing, and finishing the whole system parameter optimized distribution process. Through adoption of the system parameter optimized distribution method, optimized distribution of some difficult-to-determine parameters in the servo system and the mechanical system of the numerically-controlled machine tool is realized without complicated and cumbersome actual tests, and the system parameter optimized distribution method has the advantages of being high in efficiency, convenient to control, capable of remarkably improving the overall performance of the machine tool and the like.