Abstract: To address engineering challenges associated with traditional beeswax-based emulsion explosives—such as high oil phase viscosity, difficulty in emulsification dispersion, and susceptibility to hardening and embrittlement at low temperatures—this study introduces Vaseline as a modifier. The effects of variations in oil phase molecular structure on the rheology, microstructure, thermal stability, storage stability, and detonation performance of the emulsion explosives were systematically investigated.The results indicate that the abundant branched alkanes in Vaseline reduce the viscosity of the oil phase system and effectively improve shearing efficiency during the emulsification process. As the mass fraction of Vaseline increases from 0% to 2.4%, the Sauter mean diameter D[3,2] of the emulsion matrix decreases from 8.38 μm to 5.85 μm. Although the onset decomposition temperature T0 and the temperature of maximum weight loss rate Tp decrease slightly, the thermal stability remains within industrial safety requirements. At a Vaseline mass fraction of 1.8%, the system achieves optimal microstructural uniformity with the Polydispersity Index (PDI) dropping to 1.73. Under this condition, the resistance to high-low temperature cycles increases from 10 to 18 cycles, and the detonation velocity reaches a peak of 5180.3 m/s. This study confirms the feasibility of enhancing the comprehensive performance of emulsion explosives by tuning the oil phase microstructure, providing an economical and effective formulation optimization strategy for improving the adaptability of industrial explosives to harsh, temperature-variable environments.