Abstract: To fully understand and grasp the distribution of welding residual stress in Q460GJ thick-walled components, the strip cutting method and layered cutting method were employed to conduct post-welding residual stress testing on a Q460GJ thick-plate welded H-beam structure with dimensions of 800 mm (width) × 800 mm (height) × 42 mm (web thickness) × 80 mm (flange plate thickness). The results indicate that the post-welding unbalanced force across the full cross-section of the H-beam is only 3.3 MPa, essentially achieving tension-compression balance. At the welding junction between the flange plate and the web plate, there is a noticeable gradient in welding residual stress, with the tensile stress area on the web plate being larger than that on the flange plate. The residual stress distribution of the Q460GJ thick-plate welded H-beam is relatively close to the distribution pattern of welding residual stress in H-beam components proposed by Ban Huiyong, but there is a significant prediction error for the residual stress in some areas. Based on the experimental results, a simplified distribution pattern of welding residual stress for Q460GJ thick-plate H-beam components is proposed. The residual stress calculated using this distribution pattern does not deviate from the actual situation by more than 10%, indicating a relatively accurate approach.