In recent years, World Trade Web (WTW), also known as international trade network (ITN) was expressed by different models, including binary undirected network (BUN), weighted undirected network (WUN), binary directed network (BDN) and weighted directed network (WDN), etc. Making use of the models, scholars have analyzed topological properties (e.g., node's degree and strength), clustering (e.g., clustering coefficient) and dynamics, etc. In this paper, we express the strength of trade relations of China and the United States (or other bilateral or multilateral trade) by number or weight of subgraphs or subdigraphs in WTW instead of node's degree and strength, we also propose patterns of subgraphs or subdigraphs including only 3 nodes C (China), A (the United States) and i (a 3rd country or district) in BUN, WUN, BDN and WDN. These indexes not only overcome the limitation of node's degree or strength in WTW, but also express bilateral or multilateral trade status. In WDN, we particularly propose 16 patterns of subdigraphs in place of the traditional patterns (e.g., export, import, import and export) of trade status of a country or district, which gives a better description of trade status of China and the United States.