Abstract: With the rapid development of cross-border e-commerce industry， the explosive growth of related data in cross-border e-commerce has made data security issues increasingly prominent. Traditional cross-border e-commerce platforms often face issues of data leakage， tampering， and untrustworthiness， leading to a decrease in the trust of merchants and users to the platform. To address this issue， this paper proposes a cross-border e-commerce data security sharing model based on zero trust and blockchain （EDSM-BZT）. Firstly， a zero trust based multi factor identity authentication scheme is designed， which combines time and knowledge factors to dynamically verify each visitor. Secondly， a trust evaluation strategy is added to the scheme to calculate the trust value of the accessing subject and achieve more fine-grained control over user access behavior. Finally， an on chain and off chain collaborative storage sub model in the model is built to ensure the secure transmission and storage of cross-border e-commerce data. The experimental results show that the model can achieve dynamic control of access authorization and efficient storage of cross-border e-commerce data， with good performance and scalability.

Key words: blockchain, zero trust model, EDSM-BZT model, collaborative storage, cross-border e-commerce data