As an advanced machining technology, virtual manufacturing has been regarded as an useful tool to carry out analysis and research work with digital model instead of practical manufacture. For the virtual manufacturing process, it is a mapping of the practical machining in computer virtual environment, no real production is created and without material or power wasting. Several typical definition of virtual manufacturing dominate in this fields were listed out, based on which expressed an explicit interpretation. Main features and three type of virtual manufacturing, such as design-centered, machine-centered and control centered virtual manufacturing were analysed respectively. The virtual manufacturing system, supported by cutter tool magazine, pallet storage, production database, material storage and NC storage, have been demonstrated in an architecture figure. Finally, the author concluded the important role of virtual manufacturing and illustrated an example of applying virtual manufacturing in five-axis machining process.