SCC life estimation is very important to maintain the safety of nuclear power plants. One of the main research tasks in SCC life estimation is the evaluation of welding residual stress, which is the dominant stress causing SCC of nuclear power plants. Although some analytical research works have been conducted to clarify the welding residual stress, most of them are 2-dimensional analysis. In this paper, the authors report the residual stress of girth weld pipe obtained by axi-symmetrical and 3-dimensional numerical analyses, and these analytical results are compared with experimental residual stress measured by neutron diffraction method. It is concluded that the 3 dimensional analysis shows good correlation with the measured result. And, if the temperature history is well simulated, the difference of residual stress between aid-symmetric and 3 dimensional analyses is relatively small so that axi-symmetric analysis can be used for preliminary residual stress analysis.