As an action principle or action logic of applying through all fields of fiscal affairs and measuring whether financial activities are in line with the ultimate goal of fiscal practice, the basic logic of finance, on one hand reflect and express financial essence, on the other hand extend and present the idealistic logic of public power in financial field. According to the financial essence theory(we can also call it public power security theory), which based on the need spillover theory, the basic logic of finance is a kind of action logic about how to ensure the public power achieve its idealistic goals through exploring and allocating financial resources. As well, the basic logic of modern finance is the extension and presentation of the power logic of popular sovereignty in financial field, also the extension and presentation of publicness logic of altruism by justice in financial field. That is, explore and allocate financial resources by the rule of need justice to ensure public power to achieve its final goals of solving the need spillover affairs by the rule of need justice. In this sense, finance take the basic logic of public administration (public power logic) as its own basic logic, thus it is a public administration field which use the principle of public administration(altruism by justice) to govern the skills of finance management(including explore and allocate).