Abstract: In order to study the effect of the softening of welding heat affected zone (HAZ) on the operation security of pipeline, the effects of weld geometry size on bearing capacity of submerged arc welded pipe with double-side longitudinal seam under bearing internal pressure conditions were simulated and analyzed by finite element simulation based on the ANSYS software. Results show that the maximum stress occurs in HAZ because of the softening effect and the weld reinforcement, as well as the weld geometry size. As the penetration depths of both the inside and outside weld seams are at certain values, there exist the optimal matchs between the maximal bearing pressure and the weld widths of both the inside weld and the outside weld. As the weld widths of weld seams are at certain values, the moderates increase of penetration depths of both the inside and outside weld seams can increase the bearing capacity. In addition, the weld geometry size can affect the location of maximum stress occurred.