<p>Blockchain-based traceability is essential for ensuring the transparency and integrity of data across diverse domains. In this study, a novel cross-domain blockchain data traceability algorithm is proposed that leverages a secondary chain structure to achieve rapid and secure information traceability. By integrating blockchain technology with a secondary chain, the proposed algorithm significantly reduces update and query times, enhances data security, and ensures efficient traceability operations. A unified encoding scheme is designed for cross-domain data, including structured data (e.g., numerical and textual data) and unstructured data (e.g., images, audio, and video), to enable unified traceability. The algorithm sets unified codes for all data types, managing code resources uniformly across domains. This provides robust data support for efficient traceability operations. Through comprehensive simulation experiments, the proposed method was evaluated against existing methods, and the results show that it achieves superior performance in terms of keyword update time, keyword query time, encryption and decryption time, and execution time of traceability operations compared to existing methods. Statistical analysis of the experimental results reveals substantial enhancements in algorithm efficiency, with a 30% reduction in keyword update time and a 25% decrease in keyword query time. Moreover, encryption and decryption time are reduced by 20%, while traceability operation execution time is improved by 15%. This research contributes to advancing data traceability techniques and has promising applications in various domains. These results demonstrate that the proposed method provides an effective solution for rapid and secure cross-domain blockchain data traceability.</p>