Abstract: National governance is based on the mutual support between the state and society, while the political system capacity is the executive capacity of the political system, which is mainly reflected in the practical and positive results of the political system in building the mutual support between the state and society. Therefore, the political system capacity is the fundamental support of national governance and fundamentally determines the rise and fall of national governance. The causal relationship between political system capacity and national governance is determined by the nature of national governance. The capacity of political system originates from the shaping process of the relationship between the state and society. It takes the institutions, actors and ideas as the raw materials, while crisis challenge, competitive pressure and mission guidance constitute the power of the development of political system capacity. This means that the political system must adhere to reform, innovation and development, so as to constantly shape strong capacity.