Sino-U.S relations are maybe todays most significant and influential topic in the field of international relations. Ever since the normalization and rapprochement in 1972，which was heavily related to the strategic imperatives of the Cold war，the two countries were involved in intense cooperation in various fields，and their ties (mostly economic ones) became so attached until a deep interdependence started to prevail. Even when bilateral crisis arose throughout the short history of formal modern relations between the U.S. and China，ties were not affected，but only kept on increasing. This type of relations，according to one of today’s international relations most distinguished and prominent theory，Liberalism，should create a“commercial pacifism”between the two states，base their relations primary on commerce and economic and also lead to good American public perceptions on China. However，this is not the case，as American public perceptions on China remain negative，regardless the ongoing improvement in ties and relations. Why is that?　　This thesis aims at creating a better understanding for this puzzle between ties and perceptions in U.S.-China relations. By examining two main additional international relations theories- Neo-Realism and Constructivism，we will explorer U.S.-China relations and try to trace the reasons which lead to this disconnect in their relations. These additional theories will be investigated against the most recent public polls and surveys in the U.S. which related to Sino-American relations，providing us the practical background which is needed in this kind of research.　　We hope that the conclusion of this thesis will not only provide a better foundation for grasping the nature of U.S.-China relations and the reasons for the paradox in their relations，towards future suggestions on how perceptions might be improved，but also set a foundation for another cases in the international relations，similar to ours.