As a key direction in the digital transformation of the construction industry, smart construction utilizes technologies such as IoT, cloud computing, and big data to enable intelligent site management. However, managing distributed transactions in large-scale data exchanges and concurrent operations presents significant challenges. Traditional distributed transactions suffer from performance bottlenecks and consistency issues, particularly in high-concurrency environments where balancing transaction latency and data consistency becomes difficult. This paper introduces Decor, a solution designed to optimize distributed transactions in smart construction scenarios. Decor combines speculative techniques with Multi-Version Concurrency Control (MVCC) to reduce lock hold time by up to 60%, increasing transaction throughput by 67%, and cutting abort rates by 50%. This improves the efficiency and reliability of transaction processing, making it better suited for the complex business demands of smart construction.