ABSTRACT As the WTO and its predecessor the GATT have been remarkably successful in reducing tariffs over the past decades, non-tariff measures have replaced tariffs as a major form of trade barriers. Armed with its moral superiority, legal legitimacy and economic particularity, animal welfare trade barrier emerges as a new type of non-tariff trade barrier and has been widely used by countries—especially the developed world—to counter import of animal products from other countries. The deployment of animal welfare trade barrier has become a severe strike against developing countries that rely heavily on export of animal products. Despite the fact that the articles of various WTO agreements render certain level of legal support and basis for the adoption of animal welfare measures as adopted by the developed countries, these same WTO agreements further require that the application of such animal welfare measures to be properly construed so that neither would they constitute a means of arbitrary or unjustifiable discrimination between countries where the same conditions prevail nor would they serve as a disguised restriction on international trade. In this thesis, several cases are analyzed under the WTO legal framework in order to demonstrate the interaction of WTO rules and this new creature of non-tariff trade barrier and to illustrate the evolvement of the WTO's attitude toward animal welfare issues with respect to international trade. Considering the unique non-economic feature of animal welfare trade barrier, this thesis discusses from the perspective of the international community as a whole, how the international community addresses the tension between the need to foster trade liberalization and the honoring of animal welfare. As a typical agriculture-based economic body, China is already facing a series of challenges in its painful process of integrating with the global economy. In recent years, the export of China's agricultural products is often restricted by the non-tarifftrade barriers of the target countries, of which animal welfare trade barrier is one of the most typical and damaging ones. Compared to the developed countries where animal welfare law has been construed for a relatively longer period of time, China has not yet established a real animal welfare law and its legal system unfortunately has many deficiencies with respect to supporting implantation of animal welfare and corresponding concepts. Key words: Animal Welfare, Non-tariff Trade Barrier, W TO, GATT