Digital twin of CNC machines tool helps improve the efficiency of the machining process with the ability to monitor, optimize and predict the behavior of the physical model. In the components of the digital twin, the virtual model of the CNC machine performs the task of behavior monitoring and production preparation based on simulation technology. This paper deals with building a digital twin of a CNC milling machine using NX 1953 software. From there, it serves as a research basis to develop the process of building digital twins for future types of CNC machine tools.