Abstract: A thermal structural coupling numerical model was established for the connection of the pillars in a double-layer liquid hydrogen spherical tank. The stress and strain distribution of the connection between the pillar and the inner tank in a large liquid hydrogen spherical tank was studied, and the influence of different connection forms on its mechanical properties and heat transfer performance was analyzed. The results show that the maximum stress and strain increase significantly regardless of the connection structure between the pillar and the inner tank when considering the temperature load. Among the four types of connection structure between the pillar and inner tank, the straight circular connection structure has the least stress value at the most dangerous location, with the maximum stress value of 331.33 MPa, while the direct connection structure has the best thermal insulation performance, with a heat flow density of 758.75 W·m⁻². Since all four connection forms can meet the stress verification conditions, it is recommended to use a direct connection structure as the connection method between the pillar and the inner tank from the perspective of reducing heat leakage. The results can provide theoretical guidance for the design and selection of the connection between the pillar and the inner tank of large liquid hydrogen spherical tank.