The environmental protection of international maritime transport services is a legal issue not only of international environment but also of international services trade. During protecting the environment in the course of international maritime transport services, every country should exercise its national sovereignty restrainedly, perform international obligations in good faith, impose the exception of protecting human, animal or plant life or health by prudence and should not hinder the liberalization of maritime transport services. In order to realize goals of environmental protection of maritime transport services ultimately, we should enhance the enthusiasm and initiative of developing and the least developed countries for taking part in environment protection of international maritime transport services by international cooperation and carrying on the principal of“common but differenced responsibility”really.