Abstract: Focusing on the inevitable insecurity and temporary nature of rights in the state of nature, Kant proves the reality and necessity of entering the state of public right with the concept of the original contract. Establishing universal rules and justifiable rational courts through the power of the common will, and then legally compelling the parties to assume moral obligations based on public recognition is the fundamental condition for guaranteeing and assuring each individual’s property and achieving equal and free value. The united will, mutual responsibility and equal freedom have become the normative premise for establishing the status of public right, and it is also a vivid manifestation of the public value orientation of Kant’s conception of autonomy. In this sense, there are many differences between the Kantian and the traditional natural law theory or social contract theory approach on justification of public right.