Abstract: Multiple factors influence the mechanical response of horizontal directional drilling pipelines during both construction and service period. However, existing theories and calculation methods are notably relied on empirical correction parameters. Based on field measured data, finite element numerical simulation was employed to investigate the stress deformation of steel pipes during the back-pulling process of horizontal directional drilling construction, as well as their structural stability under external pressure. Simulation results revealed that the von Mises stress and longitudinal bending moment at the exit end of the steel pipe were significantly higher compared to those at the entry end during the back-pulling process. Additionally, in the curved section of the borehole, both the von Mises stress and longitudinal bending moment of the steel pipe increased as the curvature radius decreased. In cases of structural buckling instability under external pressure, plastic strain primarily accumulated at the top, bottom and sides of the pipe. Furthermore, the external pressure the pipe can withstand increased with increasing wall thickness and decreased with increasing diameter.