This article analyzes the conflicts of international law on genetically modified (GM) food labeling and explains possible methods to harmonize these conflicts. One way is to interpret the treaties of the World Trade Organization (WTO), Biodiversity Convention, and the International Court of Justice (ICJ); the other way is to enhance cooperation among international institutions and treaties, such as WTO, Biodiversity Convention, Codex Alimentarius Commission (CAC), International Law Commission (ILC), and the United Nations Environment Programme (UNEP). These methods cannot form an international standard on GM food labeling accepted by most countries. The difficulties with this issue concerned illustrate that GM food labeling shows off conflicts between trade law and environmental law, which lead to legal chaos that is faced with uncertainty of technology, fragmentation of international law and diversity of domestic law, and complexity of national interests on environmental labeling and process labeling.