Traditionally, UNCLOS stipulates that States have the obligation and responsibility to protect and preserve the marine environment and exercise their rights in Principle of Non-Discrimination with respect to foreign ships visiting to port states. UNFCCC and Kyoto protocol established Common but Differentiated Responsibility as the basis which is established on the historic responsibility. The principle in which IMO is presently developing the regulations of Green House Gas emitted from ships is contradict with the principle of UNFCCC regime. In this paper, the development and the principle of UNFCCC and Kyoto protocol is surveyed and it provides the tendency of the IMO activities regarding GHG emission from ships. Also, through consideration of the problems and restrictions drawn from comparison between two principles, the conclusion suggests the fundamental theory and implementation means in order to carry out the purpose of IMO regulations in accordance with the principles of UNCLOS and IMO Convention.