Abstract: In order to effectively enhance the efficiency of CNC machine tools for design, development and commissioning, virtual commissioning technology can save the cost of machine tool debugging and reduce the risk of in-site running-in. A method of software-in-the-loop virtual commissioning for CNC machine tool based on NX MCD is presented in this paper. By creating a virtual PLC via PLCSIM Advanced and utilizing TIA Portal as data communication and real-time monitoring, taking the joint simulation of CNC machine tool and PLC programme as the application, the feasibility and effectiveness of the means that is proposed in this paper has been proved. Furthermore, it provides an idea of the design and commissioning for CNC machine tools and automation equipment.