Abstract: As the soil in the water network area is soft and has large water content, it is very easy to settle, which applies an axial load to the pipeline, and the girth weld under the action of tensile load has a higher risk of failure. In order to ensure the intrinsic safety of the pipeline, a nonlinear finite element method was adopted to establish a numerical calculation model for the axial stress and strain of the pipeline under sudden settlement of soft soil based on the X80 pipeline with a diameter of 1 422 mm in the water network area, and thus the influence of different settlement displacements of soft soil on the size and distribution of the axial load of pipeline under the most unfavorable sudden displacement condition was studied. On this basis, the safety of pipeline welds at different locations in the soft soil settlement area was evaluated according to the Guide to Methods for Assessing the Acceptability of Flaws in Metallic Structures (BS 7910-2019). Meanwhile, the influence of external load conditions and weld misalignment was analyzed, which indicates that the increase of misalignment leads to an increase in the load ratio and toughness ratio used in the assessment, with the conservativeness reduced for the safety of pipeline. If the critical Crack Tip Opening Displacement (CTOD) is taken to be 0.25 mm in the current standard, and the level-1 assessment curve is adopted, the welds of X80 pipeline in the water network area are always in a safe state. If the level-2 assessment curve is used, the X80 pipeline weld is in a critical safe state when the critical CTOD is reduced to 0.08 mm and the settlement displacement takes the maximum value of 1 m.