With the popularization of computer and network technology, data with proof and legal effect has gradually changed from physical to electronic, and electronic documents have gradually become an important carrier and tool for transmitting information and recording facts. Electronic evidence has the characteristics of easy storage and high security, which also imposes high requirements on network security and other aspects. How to effectively preserve electronic evidence and fully trace its source when necessary has become an important research issue. This paper proposes a method to achieve efficient preservation and traceability of electronic evidence through the combination of blockchain, Image-Caption and word segmentation technology. When using blockchain technology to ensure the non-tampering and anti-repudiation of electronic evidence, ensure that electronic evidence While improving the authenticity and integrity of electronic evidence, it improves the traceability and accuracy of electronic evidence.