The key to global climate justice is how to define or distribute greenhouse-gas( sometimes abbreviated to GHG) emissions rights in different countries. Three questions are to be answered: First,what does global climate justice distribute? Second,on what principle does it distribute?Third,what is the moral foundation of the principle? The thesis analyzes the peculiarity of GHG emissions permit as a global public resource and its consequent ethical issues. On the ground of egalitarianism,it proves the basic principle of distributing GHG emissions permit required by global climate justice,and the basic ethical ground of global climate justice accepted by international community.