Cryogenic liquefied natural gas (LNG) tank container is the most typical equipment for transporting liquefied natural gas. It has the advantages of high mobility and flexibility. Due to the complex operation conditions of tank containers, the medium inside the tank is flammable and explosive and needs to be stored in low temperature environment, and the requirement for the cold insulation performance of the container is high. Based on the finite element theory and the actual working conditions, this paper calculates and analyzes the heat leakage problem along the axial direction of the top inlet pipe of LNG tank container by using ANSYS software, and it is found that the heat flux along the axial direction is high. The heat in the external environment is easily transferred into the tank along the pipeline and the heat transfer rate is fast. The broken bridge structure is introduced into the optimization design of the pipeline and an improved scheme is put forward to achieve the effect of heat flow blocking.