Inventory is actually stored in the warehouse of goods. Can be divided into two categories: one is the production of inventory, that the primary consumable supplies directly to enterprises and institutions of inventory, it is to ensure that enterprises and institutions can be consumed by an uninterrupted supply of materials and storage; one is the flow of inventory that producers of finished goods inventory, inventory and production departments at all levels of inventory goods department. In addition, a special form of national reserve supplies, which is mainly to ensure timely and complete manner to the primary material supply or sale of enterprises, institutions of supply inventory.