||Many simulators employ computer-generated images as part of the training process, and the concept of a virtual environment is nothing new to industry. However, immersive and interactive Virtual Reality (VR) systems will provide new training paradigms for existing and new training applications to modern industry. CNC milling machine is one of the main pieces of machining equipment in the factory. Presently, trainees acquire their operating skills by observing, referring the operation manual and then operating under the guidance of an experienced operator. To make training safer, more economical and more effective, there is an increasing desire to complete initial training away from the operating environment. In this paper, we describe a VR-based Training System (VRTS) for CNC milling machine operations in which a trainee can acquire the set of skills necessary to perform basic milling operations. Based on the analysis of possible scenarios which may occur during the operations, two patterns of virtual training: 1) guide training and 2) self-learning training were designed & developed for two different training stages. Experimental results demonstrated that VR-based training is an efficient and cost-effective alternative to standard factory training.