Abstract. Credit transactions require an extra level of security, trust, and privacy. Although the bank's credit transaction system technology has gradually improved, it still has high labour costs, inefficiencies, and security concerns. This study proposes a standardized blockchain application model in fintech and discovers that blockchain has broad prospects that can be realized through distributed consensus, smart contract execution, cryptographic algorithms, and distributed ledgers, which increase transparency, efficiency, and fairness in the financial industry. This study also deployed an automated machine learning system at the stage where banks qualify borrowers, optimizing the original credit model.