Abstract： According to the selfsupporting prismatic type B (SPB) liquefied natural gas (LNG) carriers’ heat transfer characteristics after the failure of thermal insulation layer, the coefficients of area and temperature are proposed to describe the coupling between structure temperature field and air temperature field of internal convection space. A typical partial failure model is chosen to calculate the structure temperature field and thermal stress by computational fluid dynamics (CFD) numerical simulation and finite element method, and the change of temperature and stree before and after the partial failure is analyzed to estimate the effect of the thermal insulation layer failure on the structure safety. The results provide a reference for the research on the structure safety of SPB LNG carrier.