This study was aimed at evaluation of residual stress of steel pipe structures. The production process of pipes was complex (at first bending was done by roll forming or press forming and welding was final process of making of steel pipes). So there could be expected high residual stresses in steel pipes. In order to evaluate the changes of residual stress measurements of residual stress were done for the circular pipe (thickness 16 mm). For the evaluation of residual stress, holedrilling method (ASTM E837) was applied. The results showed that along the weld line high tensile stress were measured as expected, and high tensile stresses were measured where large plastic deformation developed. And in order to assist the experimental results, numerical method (finite element method) was applied. In finite element analysis, non-linear analysis of processes was considered. In welding (final case of pipe making), thermal-elastic-plastic analysis was done considering material properties according to temperature. The calculations showed there were good agreements with experimental results. And from results, experimental results could be more effectively assisted through numerical method in welded pipes production.