【Purpose/significance】 With the deepening of financial business informatization, the rapid spread of all kinds of financial

data has promoted the financial field to enter the era of big data, and the structural transformation and dynamic development of the fi⁃nancial industry has faced new challenges. In the context of big data, the study of financial information security system is conducive to the storage and application of user information.【Method/process】 Aiming at the security dilemma of financial information at different levels in the big data environment, the specific problems existing in the current user information in the financial field are found, the prevention and measures of financial information security in the big data environment are discussed, and the corresponding security platform is built.【Result/conclusion】 By identifying financial information risks and difficulties and classifying them, the financial in⁃formation security strategies at individual, technical and institutional levels under the background of big data were sorted out, the fi⁃nancial information security guarantee system under the big data environment was constructed, and some elements of the financial se⁃curity guarantee system under the big data environment were visualized and functionalized based on the platform as an example.【Inno⁃vation/limitation】 The security system constructed in this paper focuses on theoretical and methodological analysis. In the future, it needs to further realize the real connection with financial information and test the effectiveness and universality of the system in prac⁃tice.