Unburied submarine pipelines are prone to side flexion due to high temperature and high pressure, and induce control side flexion by introducing residual curvature at the design position. Axial resistance of the soil is the key to influence the flexion. Therefore, the influence of nonlinear axial soil resistance on the cap flexion was investigated into the numerical model. The influence of various factors on the pipeline bending, including axial fault soil resistance, axial fault mobilization distance, axial residual soil resistance and axial residual mobilization distance were studied. The results show that the pipe buckling is affected by the axial resistance. Axial fracture resistance and fracture mobilization distance simultaneously affect the state before and after flexion state, while axial residual resistance and residual mobilization distance mainly affect the post-flexion state. Therefore, in the engineering design of pipeline buckling, it is recommended to carefully choose the appropriate axial soil resistance model considering the actual field conditions.