To offer the distribution of the temperature field and thermal stress for steady state convective heat transfer condition of LNG tanks on leakage occasion, the behaviors of a 1 600 000 m³ LNG outer concrete tank are studied by ANSYS. Via thermal-structure coupling analysis, cases combinations between the thermal stress on LNG outer concrete tank wall and different static forces are calculated. The most adverse envelope diagram under static load is obtained, and then the configuration of circumferential pre-stressed reinforcement is proposed. The numerical results show that the temperature stress makes the LNG outer concrete tank a shrinkage deformation tendency; the liquid pressure is the dominating influence factor on deformation and internal forces of the outer tank structure; the weakest part is located at about 10m from the bottom.