This chapter provides a combined computational and analytical study to investigate the lateral impact behavior of pressurized pipelines and inspect effects of important parameters such as the outside diameter and internal pressure on such behavior. A total of more than 300 numerical simulations are carried out on mild steel pipe models with different internal pressure levels and were struck at the mid-span and at the one quarter span positions. These numerical simulations of the impact tests are performed using 3D dynamic nonlinear finite element analysis (FEA) through LS-DYNA, where both geometrical and material nonlinearities are considered. The computational results for the first time systematically reveal the effects of internal pressure, impact position, and outside diameter on the lateral impact behavior of the pipeline models. Quartic polynomial functions are applied to formulate the maximum crushing force (Fmax), maximum permanent displacement (Wf), and absorbed energy (Ep) of the pressurized pipelines during the impact problem. The effects of the diameter and pressure on F, W, and E are therefore illustrated through analyzing those functions. Response surfaces are also plotted based on the generated quartic polynomial functions and the quality (accuracy) of those functions are verified through several techniques. The outcomes of this study have potential benefits on research of safety and reliability of pressurized pipelines in hydraulic system of aerospace and development of advanced pipeline materials.