War has always been among human race from ancient times, therefore some set of ground rules were made to make the war itself as humanely as possible. International humanitarian law is basically laws of war, the rules of the law of nations respecting warfare. It develops through time and conventions, ratified by most countries including the USA. When USA invades Iraq to save the world from mass destruction weapon said to be in Iraq and end Saddam Hussein's tyranny, the big international issue starts when USA army went ahead of the international humanitarian law and undergo extreme interrogation process which by facts are disrupting and opposing the ratified clauses on protection of war prisoner. With methods that are too degrading and too extreme of an interrogation that it should be described as torture, when the USA is one of the countries that ratified international humanitarian law and in an armed conflict, this certainly is an issue within international humanitarian law no doubt. Therefore this legal research will discuss everything from scratch, starting from the history and definition to sanctions of international humanitarian law.