U3Si2-Al dispersion fuels have emerged as promising low-enriched uranium alternatives for research and test reactors due to their high uranium density and excellent compatibility with aluminum (Al) matrix. This study investigates the effective thermal conductivity of U3Si2-Al dispersion fuels with fission gas bubbles (FGBs) by the multi-level homogenization approach and the finite element method (FEM). The multi-level homogenization approach simplifies the complex microstructure of the U3Si2 particles with FGBs and the irradiated U3Si2-Al dispersion fuels into homogeneous materials, enabling sequential calculation of effective thermal conductivity. Three-dimensional finite element models incorporating the Al matrix, U3Si2 particles, and FGBs were established to solve the heat equation and validate the developed multi-level homogenization model. The results indicate that the effective thermal conductivity of U3Si2-Al dispersion fuels with FGBs is primarily determined by the volume fraction of U3Si2 particles containing FGBs. The formation of FGBs during irradiation degrades the effective thermal conductivity of U3Si2 particles and increases their volume fraction, which in turn decreases the effective thermal conductivity of irradiated U3Si2-Al dispersion fuels. The effective thermal conductivity results obtained from the developed multi-level Maxwell-Eucken model are in good agreement with the FEM results. This study provides a foundation for the efficient numerical computation of the thermal performance of U3Si2-Al dispersion fuel elements and assemblies during irradiation.