Abstract: Describing the precise material process state is very important to calculate the production task and work out the production scheme. Based on the properties and theorem of the set named S(I), a new method is presented to describe the material process state in production management. Using the material process state vector and material process state value to deal with the materials is a concise way which provides a powerful mathematic tool for material management in production man-agement.

Key words: Material, Process state, Production management