Abstract: As the key equipment in natural gas liquefaction process, seawater-mixed refrigerant heat exchanger is mainly used for cooling/condensing the multistage compression medium (mixed refrigerant).Through plenty of investigations and experimental researches, this paper determines the heat exchanger with corrugated low finned tube/ double helical baffles structure as the preferred scheme of seawater-mixed refrigerant heat exchanger. Through quality control of raw materials, heat transfer elements, critical component and assembly process, the seawater-mixed refrigerant heat exchanger is manufactured successfully, which lays a good foundation for the development of the seawater-mixed refrigerant heat exchanger.