This article focuses on the engineering involved in removing obstacles during the pipe jacking of a drainage canal beneath an existing intercity railway. In response to the difficulties of blocked pipe jacking, high construction difficulty, major safety hazards, and tight construction schedule, the impact of artificial ground freezing reinforcement combin with undermining method on the safety performance of the intercity railway structure above is studied, through technical scheme comparison and selection, 3D finite element numerical simulation analysis, and in-situ monitoring results verification. The effectiveness of this scheme for top pipe obstacle removal engineering is explored. This project effectively manages displacement deformation and internal force changes in the existing intercity railway during construction, ensuring structural safety. It also provides valuable theoretical support and practical guidance for the design and construction of similar projects.