Abstract: LNG receiving terminal of Guangdong Dapeng Liquefied Natural Gas Limited Company was Built by EPC contract.After several years, operation, lab technicians found the original LNG sampling system had design fault, which could not take representative sample. For the LNG trade, the representative sample of LNG is the key to obtain accurate and reliable analysis results. In view of the shortcomings of the original sampling system, LNG liquid sample needs special vacuum insulation before it goes to vaporizer, and power supply for the vaporizer needs to be increased. By comparing with the old and new sampling system performance through LNG custody transfer, satisfactory results were obtained.