Public finance is a democratic finance that combines individual needs，public needs，and government financial functions. As the one from realizing the function of the state to the public needs of the society，the public finance not only has the substantive significance of grassroots government financial function transformation，but also promote the direction of change for grassroots social democratic governance. Because government finances are responsible for social and public needs，giving finances a democratic nature，ensuring the people’s political，economic，social，and cultural rights，and allowing taxpayers to enjoy greater public benefits from the government than the resource values they transfer to the government through taxes. Only in this way can make the publicity of the government and the construction of social relations at the grassroots level intrinsically linked. This is the essence of the governance of modern society.