The characteristics of blockchain technology, on the one hand, lay the possibility of its application in finance, which is an important cornerstone of civilized society, and on the other hand, lay the clues for the illegal risks in blockchain financial activities. Based on the actual financial application scenario of blockchain technology, the risk of illegal application of blockchain technology in the financial field is firstly reflected in the promotion of cryptocurrency-based blockchain financial ecology for fraudulent purchase of foreign exchange crimes and money laundering crimes. Blockchain ICO and other centralized financial activities have brought about the risk of disrupting the financial order, such as insider trading crimes and financial fraud crimes. The further development and application of blockchain technology has also given rise to crime forms in decentralized scenarios based on smart contracts. Thinking about the rule of blockchain financial crimes, the lack of current law norms and the risk endogenous nature of blockchain technology have jointly led to the difficulty of identifying related crimes. Therefore, to better cope with the criminal law risks in blockchain finance, it is necessary to follow the principle of internal and external distinction to regulate the relevant risks. From an external perspective, to bring blockchain financial crimes into the rule of criminal law, the criminal law characterization of cryptocurrencies must first be re-evaluated. In this regard, the nature of different cryptocurrencies should be discussed on a case-by-case basis. At the same time, it is also necessary to clarify the legal status of the subjects of blockchain technology development, and reasonably define the platform responsibilities of relevant blockchain enterprises and the way of supervision. The current one-size-fits-all regulatory approach should be rethought, and a regulatory sandbox model with inclusive features should be adopted to allow relevant enterprises to carry out disruptive innovations within a controlled scope, and to reasonably set platform responsibilities based on an inclusive and prudent regulatory approach. As far as the internal perspective is concerned, the rules of governance in the blockchain field also require blockchain enterprises to integrate criminal compliance requirements as internal control means. Specifically, domestic enterprises involved in blockchain information services should effectively fulfill domestic regulatory requirements; enterprises involved in blockchain financial services should effectively fulfill their anti-money laundering obligations and integrate FATF and domestic regulations of various countries to do their compliance work; enterprises involved in blockchain financial transactions should pay close attention to the criminal risks of financial transactions, establish and improve criminal compliance for financial and securities crimes; domestic and foreign enterprises involved in the development of blockchain smart contracts should actively promote the integration of corporate criminal compliance and blockchain code. By improving the regulation and rules of blockchain both internally and externally, and prompting the criminal law to respond positively to blockchain financial crimes, it will help to better promote innovation in the field of blockchain finance and help China's digital economy to move steadily and far.