Cost reduction and efficiency enhancement involve the whole life cycle of project design, procurement, construction, operation and maintenance. However, engineering design is the key link of cost reduction and efficiency enhancement in natural gas purification project.The main way of cost reduction and efficiency enhancement in design phase is to reduce project investment, save energy and reduce energy consumption.The measures of reducing cost and increasing efficiency in engineering design stage are discussed with regard to the process of desulfurization, dehydration, sulfur recovery and tail gas treatment of natural gas purification project.It is concluded that design can be optimized the and investment be reduced by optimizing the overall process plan, process plan and process flow of the plant, properly selecting equipment and valves, practicing inter-discipline collaborative 3D modeling in construction drawings, and performing joint examination for 3D model, promoting modular design and other measures.The design can be optimized and energy consumption can be reduced by optimizing desulfurization device, dehydration device, sulfur recovery device, tail gas treatment device.The results can provide reference for reducing cost and increasing efficiency of natural gas purification projects.