Based on different understandings of China’s system of ethnic regional autonomy both at home and abroad,this paper examines the system from the perspective of the history of rational development in Western countries so as to strengthen the power of international dialogue in the construction of discourse system of ethnic regional autonomy in China,and enable us to have a full understanding and grasp of the system which is one of the basic political systems in China. It also analyzes China ’s ethnic regional autonomy in perspective of five rationalities of Western countries which are: empirical rationality,practical rationality,instrumental rationality,value rationality and communication rationality,and points out that ethnic regional autonomy has its own developmental logic. It is established,developed and improved in the practice of Chinese revolution and development through absorbing the historical experience of China’s grant unification,and it is the basic political system of the State which represents the basic interest and fundamental requirements of the people of all ethnic groups in China.