Abstract: LNG is a multi-component mixture and its heat leakage to outside can cause many problems and influence the safety and economy inpipeline transmission. In the case, understanding the change law of LNG evaporation rate and pressure under heat leakage has greattheoretical significance in the design and management of LNG pipeline. Based on the change laws in insulating layer thickness, LNG vaporization ratio and thickness of pipe wall, adopting cold-state transport method should be made to increase pipeline pressure bycontrolling the thickness of thermal insulation materials in order to eliminate LNG's vaporization, which will be an available way to promote flowing of LNG and optimize transport technology. Establishing the economic mathematical model for LNG pipeline transport to obtain the best vaporization ratio and thicknesses for pipe and thermal insulation layer is important, and the economy and cost of pipeline systems can be optimized by this way. Adaptability for the model and its calculation program in pipeline project is given with a case.