The purposes of this study are firstly to construct an operational equitable initial rights allocation model. Then, it is to determine the equity principle under cost effectiveness for countries with different levels of economic development. The same analytic process is applied to China, India, and the United States. The results show that the attractiveness for the groups of upper middle-income and low middle-income countries to join the emission reduction array are much easier than the other groups of the countries since the lowest total abatement cost for those groups with emission trading will occur at the same equity criterion as those without emission trading. As with China, India, and the United States, the lowest cost occurs at full capacity weight of GDR framework, egalitarian, and sovereignty respectively. It is thus a challenge to bring those three countries into the emission trading array due to such equity discrepancy between individual country and the world as a whole.