Abstract: Computational fluid dynamics methods were used to analyse the influence of the fluid-structure interaction (FSI) between pipe and external fluid coupled system. The vertical pipeline system was investigated, and the interaction between the external fluid and pipe was solved with the application of numerical methods for the nonlinear fluid-structure problem. These results were shown that: 1) whether the connection modes of lifting pipe on top end were fixed or hinged, the impact of the external flow field at different speeds on pipe brought the concentrated stress in the location close to the connection area. The maximum stress appears at the top of the pipe connection point while the stresses of the remaining parts in the pipeline had little fluctuations; 2) its maximum equivalent stresses were increased with the external flow velocity up. The values of the pipe’s maximum stresses produced by a fixed connection were always greater than that of the hinged connection. 3) in despite of fixed or hinged connection, local minimum stress appears when the external fluid velocity is 0.9m/s. In contrast, the local minimum stress value generated by the fixed support was less than that by hinged connection .