Abstract: The Third Plenary Session of the 18th Central Communist Part of China proposed that public finance is the foundation and important pillar of national governance, and the strategic development of building modern fiscal system. This paper discusses the development of the theory of national governance from "rule mode" to "governance model", and the media effect of fiscal system in economic, political and social subsystem. Based on the key position of fiscal system, this paper states how to build modern fiscal system from the perspective of budget system, tax system and government relationship, in order to promote national governance mode transformation, and the governance capability. At present, the new normal that our country has entered “the finance of a big country” has become an indisputable reality, so the construction of the finance of a big country and a modern financial system, not only plays a financial role of safeguarding a country, but also plays a greater role of Chinese finance in global governance.

Key words: national governance, modern fiscal institutions, the finance of a big country