The relationship between international trade and environmental protection is a contentious issue. International trade agreements aim for free trade, while environmental agreements restrict trade to protect the environment, leading to potential conflicts. Various environmental agreements introduce trade restrictions for environmental protection, sparking debates on which should take precedence. The WTO has prioritized free trade over environmental protection in some cases, but has ruled in favor of environmental protection in others. The resolution of conflicts between trade and environmental protection can be addressed through international customary law and treaty law, but true harmony between the two requires a focus on environmentally sustainable development.