Although supply chain finance is essential for modern business, it is also prone to fraud, mistakes, and inefficiencies. This paper presents a blockchain-based smart contract audit system to improve supply chain finance’s security, openness, and efficiency. The system uses distributed architecture, smart contracts and blockchain technology to automate and audit financial transactions. In terms of scalability, convergence speed, and accuracy, experimental results reveal quite excellent performance of the proposed system. The proposed method achieved in auditing financial transactions an accuracy of 95.2%. Showing a convergence speed of 41.2 s for 30 nodes, the system confirmed its ability to manage large-scale datasets. With 30 nodes, the system shown scalability proving it could control difficult supply chain financial circumstances. Promising supply chain finance solution the blockchain-based smart contract audit system shown a clear decrease in audit time and cost.