China and the United States are the two most important WTO Members. From the perspective on the surface, the Sino-American trade frictions are caused by their domestic systems. Nevertheless, they are intertwined with the WTO rules due to the fact that the trade regime under the WTO is a rule-oriented system. Although the WTO rules have no direct applicability within its members, the members should keep their domestic trade laws and policies consistent with the WTO rules. Moreover, the legal status of the members and the relationships between them within the WTO are also regulated by these rules and customary international law. Any change concerned with the multilateral trade regime and interests of WTO members may cause a huge response. Under this circumstance, the study on Sino-American trade relationship should not be limited to the domestic laws of these two countries, but extended to the whole WTO rules. Meanwhile, the conclusions resulting from the study on Sino-American trade relationship may also help us to have a better understanding on the development of the multilateral trade regime.