<p> <?tk 4?>With the rapid development of sensor network technology and the popularity of big data applications, sensor networks have been widely used in the field of network finance, providing rich data sources for financial institutions. But with this comes the challenge of big data privacy protection and online financial risk management. This study aims to explore how to achieve privacy protection of big data based on sensor networks, effectively manage network financial risks, and provide safe and reliable data management solutions for financial institutions. This paper analyzes the privacy problems existing in the data transmission and storage process of sensor networks, and puts forward the corresponding privacy protection strategies. Combined with data encryption, access control and other technical means, build a secure data management mechanism; Finally, the risk assessment model and data mining technology are used to realize the effective management of network financial risks. After experimental verification, the sensor network-based big data privacy protection and network financial risk management method proposed in this study can effectively protect private data and reduce network financial risks, and has achieved good application results.</p>