Abstract: The commissioning quality of CNC machine tools in the commissioning stage directly affects their machining accuracy. However, CNC machine tools in the service stage are rich and varied in processing scenarios, and as the representative equipment of complex electromechanical systems, they contain massive and complex coupling relationships. Therefore, the effectiveness of general commissioning methods in this case is very limited. Therefore, this paper proposes a way to simulate the complex machining scene of machine tool running in virtual environment and carry out virtual commissioning to get the best running parameters. Firstly, by analyzing the complex coupling relationship of electromechanical system, a digital twin model of CNC machine tools was constructed using multi-domain unified modeling language combined with virtual-real mapping strategy. Secondly, the complex machining scene was simulated based on the twin model, and the virtual commissioning method of NC machine tool was proposed. Finally, a numerical control machine tool spindle system is taken as an example to verify the effectiveness of the proposed method and the feasibility of field application. The experimental results show that the response time is reduced by 12% and the steady-state error is reduced by 54%.