Virtual manufacturing systems that perform production activities ahead of real production in virtual world can reduce time and cost to develop, design, plan, and manage new products. In this paper, a virtual manufacturing system is constructed as a tool to support decision making by using VRML and Java. The basic structure of the virtual manufacturing system and the operation models are also presented. The developed system helps any related persons to share design and manufacturing information, and to perform their tasks collaboratively through Internet. The other function of the system is to monitor operation status in real time.