To address the modeling problem of electromagnetic interference (EMI) multipath coupling propagation in complex enclosed environments, this paper proposes an EMI coupling path analysis method based on a weighted topological network model. According to the specific electromagnetic environment and coupling propagation modes, a multi-level shielding topology is constructed, defining a three-tier node system comprising cabin walls, equipment enclosures, and PCBs, and establishing coupling mechanisms for both radiation and conductive paths. A dynamic edge-weight function is designed, integrating frequency-dependent S-parameters, material conductivity, and time-varying field strength characteristics to quantify the coupling weights of radiation and conductive paths. Furthermore, a node sensitivity dynamic mapping model is introduced, enabling the identification of sensitive nodes through an inverse proportional threshold of shielding effectiveness. A Python-based computational toolchain for engineering applications is developed for simulation experiments. The results demonstrate that this method can accurately characterize coupling effects such as aperture leakage and cable crosstalk, providing theoretical support for electromagnetic compatibility design and interference suppression in enclosed environments.