For the related research on taxation law in the field of crisis in mainland china, there are two major drawbacks: theoretical vision limitations and insufficient practical attention, which hinders the legalization of taxation law, need to be improved. The practical transformation of the connotation of the legal principle of taxation and the diverse interpretation of the theory of people’s sovereignty behind it, shows that the preferential taxation policy issued by the administrative agency does not violate the requirements of the legal principle of taxation in nature, and is a formal rational choice. From the perspective of legitimacy, the model authorized by the law grants the administrative agency the right to reduce or exempt tax incentives; from the perspective of rationality, although the lack of procedural protection mechanism needs to be improved, the provisional sunset clause in practice and the the preferential tax measures based on the security, meet the requirements of moderation. At the same time, in the response to ’’Balance of Revenue and Expenditure’’, the government did not increase taxes and fees to achieve a balance of budgetary revenue and expenditure. Instead, it adopted a proactive fiscal expenditure policy and debt issuance, indicating that the preferential tax measures did not cause the increase in taxpayers’ tax burdens, which in turn produces injustice. And it’s substantively rational.