Abstract: To enhance LNG cold energy recovery, minimize environmental impact, and improve the economic performance of the system, a multi-objective optimization method based on the NSGA-II genetic algorithm was employed. A poly-generation system integrating LNG cold energy recovery, a Three-stage Rankine cycle(ORC), carbon capture, and cold-chain refrigeration was proposed. By optimizing parameters such as turbine inlet temperature, condensation temperature, and working medium flow rate, the system 's exergy efficiency increased from 45.5% to 50. 1%, unit electricity cost decreased to 4.6 ＄/GJ, CO₂ emissions were reduced from 40 kg/GJ to 30 kg/GJ. These results demonstrate that the integrated poly-generation system significantly improves energy efficiency, reduces environmental impact and operating costs, and offers a promising solution for efficient energy utilization and sustainable development.