<p>This study evaluates the structural safety of a Type I hydrogen pressure vessel under the combined effects of welding residual stress and cryogenic loading through thermostructural coupled finite element analysis. Welding simulations employing the element birth technique revealed a maximum tensile residual stress of 239 MPa in the base metal region adjacent to the boss connection. In addition, under cryogenic operating conditions (internal temperature of −253 °C, external temperature of 20 °C) and an internal pressure of 0.5 MPa, the combined effects of welding residual stress, cryogenic thermal stress, and pressure-induced stress were assessed. According to the ASME Section VIII Division 2 criteria, the membrane stress (<Emphasis Type="BoldItalic">P</Emphasis>_{<Emphasis Type="BoldItalic">m</Emphasis>}) was lower than the allowable stress intensity (<Emphasis Type="BoldItalic">S</Emphasis>_{<Emphasis Type="BoldItalic">m</Emphasis>} = 367 MPa), and the sum of local membrane stress (<Emphasis Type="BoldItalic">P</Emphasis>_{<Emphasis Type="BoldItalic">L</Emphasis>}) and bending stress (<Emphasis Type="BoldItalic">P</Emphasis>_{<Emphasis Type="BoldItalic">b</Emphasis>}) was lower than the allowable stress intensity (1.5<Emphasis Type="BoldItalic">S</Emphasis>_{<Emphasis Type="BoldItalic">m</Emphasis>} = 551 MPa). Therefore, the linearized stresses in the inner pressure vessel satisfy all applicable allowable limits, confirming its structural integrity. The maximum stress occurring at the welded boss region (446 MPa, consisting of tensile residual stress of 239 MPa, thermal stress of 191 MPa, and pressure-induced stress of 16 MPa) is lower than the material yield strength at cryogenic temperature (665 MPa), indicating structural safety. These results validate the applicability of Type I pressure vessels for liquid hydrogen storage.</p>