This study explores the construction mechanism of the supply chain ecosystem in the Hainan Free Trade Port against the backdrop of the digital economy. By designing a supply chain traceability model and combining differential privacy algorithms with blockchain technology, a solution that balances data privacy protection and sharing efficiency is proposed. The economic effects of closed-loop supply chain strategies under different platform models are analyzed, and based on the geographical and policy advantages of the Hainan Free Trade Port, a path for its integration into the global supply chain network is proposed. Through an analysis of the supply chain impact in the Hainan Free Trade Port, it is found that when the construction cost of blockchain is sufficiently small ( F → 0 ), there are two thresholds, 0 < α1 < 1 < 1 , such that 1 < α < 1 then introducing blockchain technology can increase corporate profits, i.e., π*B > π*N; otherwise, introducing blockchain technology will reduce corporate profits, i.e., π*B < π*N There exists a threshold F1 : 1) When α < 1 and F > F1 , then ∏*N > ∏*B and π*N > π*B ; 2) When α < 1 and F < F1 , ∏*N > ∏*B and π*B > π*N ; 3) When α > 1 and F > F1 , then ∏*N > ∏*B and π*B > π*N ; 4) When α > 1 and F < F1 , then ∏*B > ∏*N and π*B > π*N.
