With the continuous expansion of cross-border e-commerce scale, logistics security has put forward higher requirements for verifiable data flow, tamper-resistant records and timely location of abnormal nodes. This paper constructs a blockchain-based secure data traceability mechanism for cross-border e-commerce logistics, which integrates event standardized coding, hash anchoring, smart contract verification, alliance chain collaboration and audit writeback into a unified implementation framework. The mechanism covers data access, index construction, on-chain execution, consistency audit and traceability query, and can support the trusted association between order events, warehousing records, customs status, transportation updates and receipt information. The experiment was carried out on the Fabric test platform consisting of 28 nodes and 1.26 million logistics records. The results show that the proposed method achieves 2147 TPS, 1.84 s average confirmation delay, 98.6% tracking accuracy and 96.9% abnormal node location accuracy, and maintains a relatively stable output under the conditions of high concurrency, field tampering and signature replacement. The mechanism can provide reliable data support for supply chain collaboration, supply chain financial verification and e-commerce supervision.
