This paper is about the historical origination of ”autonomy” and its systematical meaning related to the idea of democracy. The concept of autonomy is raised for the independency of the communities in which people identify themselves as free and equal citizens, but under the threat of other powerful states. Afraid of being treated as inferior and second-class citizens, they have to defend their rights and interests. The conflict between communities is related to their identity and belief, who they are and what they ought to do, sometimes, it may not possible for them to reconcile with each other. But the problem is not how to reconcile their incommensurable positions, but how to defense their autonomy, not being overridden by other unjustified power. For the need of keeping the value of autonomy, the procedure of democracy has a cognitive function through which the citizens can figure out what they should and should not act.