Network Organization is an organization built by some rules among organizations for some purposes or some tasks. For example, many organizations work together to develop a new product. The technology of directed graph and fuzzy design structure matrix are used in the development of a new product in the network organization. Base on this, the methods of task de-coupling, matrix exchange and partitions are used to optimize the design activity. It can improve the rate and efficiency of the product's development, reduce the problem of design iteration, short the development periods, make the members of the network organization work concurrently without damaging the quality of the products.